Team and their coach. So far, rescue teams successfully evacuated four boys from the cave. Really a system of caves and tunnels. The remaining eight boys and their coach spending another night in the depths of that dark cave, where they have been trapped for more than two weeks. Its a race against the clock. Oxygen levels are depleting rapidly, and heavy rain is on the way, threatening to flood the cave. Right now, rescue workers are just wrapping up a strategy meeting to plot out their next move and divers are refueling their oxygen tanks before the next mission as families wait anxiously for the remaining kids to start the treacherous journey to safety. Cnn has reporters on the ground. Jonathan miller near the cave entrance, and cnns matt rivers outside the hospital where the four boys are now being treated. Lets go first to jonathan miller. This was an extraordinary rescue. Some call it miraculous. And theres still a long way to go. How did they pull this off . Reporter well, joe, what we now know about this perilous operation was it involved 90 rescue workers in total. 13 of them divers. And an additional five thai navy s. E. A. L. S. What we understand is that each of the four boys who came out was individually accompanied by two divers. One in front, one behind. The lead diver held the compressor, tank, of the boy who was leading out. And the boy was tethered to him. There was another diver behind, using that guideline. And they came out through all those flooded subterranean passageways. We know there were at least four or five sections completely flooded still, the longest of which was about 30 yards long. Now, this evening about two or three hours ago, the governor of chiang rai province, who has shouldered the huge responsibility in leading this rescue mission had the full blessing of the parents to go ahead with this. He gave a little more detail about what went on down there today. Translator all the boys are wearing full face masks, and the rescue divers carried them out through the passage in the cave complex. Reporter well, weve got four out. There are eight more to go, plus the coach. And they have to stay down there for the next few hours, probably couple of days, actually, because the there are theres a problem with restocking the oxygen supplies down there. The oxygen tanks, which had been prepositioned. The other problem theyve got is this is being described as a war against water and a race against time. As you can probably see behind me, it is pouring, and has been for hours. And, of course, this is a huge catchment area, and as the water comes down, that cave system will fill up again. So they need to get the boys out quickly. Jonathan, first question thats on my mind is, do we know how much of this journey to safety for these boys is essentially hiking and sliding through caves and narrow spaces, and how much of it actually involves essentially scuba diving . Reporter yeah, well, as i say, there are several passageways that are that remain completely submerged. So we dont know the total distance, but it would have involved several phases in which there would have been proper scuba diving. Now, the boys have been fitted with these full face masks, they breathe through their nose. They have been trained down there by navy seef. E. A. L. S in h to do that. But there would also have been, as you say, joe, several climbs. And squeezes through incredibly narrow passageways. We know they were so narrow that the divers will to take the oxygen tanks off their backs to squeeze through. So, i mean, the boys came through it, but albeit in very different conditions than when they went down those two weeks ago. Now, the other question, of course, do the other boys, the ones who are still inside, have any idea, along with the coach, that these first four have actually made it to safety . Reporter we still dont know that. And it must be terribly worrying for them, not knowing whats going on. We remember just three days ago that thai navy s. E. A. L. Experienced diver tragically died about a mile underground. So we know how difficult this is. The boys will be anxious about it. But the letters they sent up yesterday to their parents urged them not to worry, showed them to be in relatively high spirits. And looking forward to birthday parties and seeing friends and eating Fried Chicken again. So theyre all very hopeful of getting out, but we dont know yet whether their friends have made it to safety. Those letters certainly did show a lot of spirit and resilience, which we all know comes with young kids. Thanks so much for that, be jonathan miller. Well check back with you again. After that intense rescue mission, the boys were rushed to a hospital about an hours drive from the cave. Doctors and nurses there have been preparing for days in anticipation of treating the first boys. Lets check in now with cnns international correspondent, matt rivers, right outside the hospital. Matt, what are you learning about the condition of these kids . Reporter yeah, joe, we saw four different ambulances come here as part of a couple different convoys with military and Police Vehicles attached as soon as they were taken out of that cave. They were loaded into these ambulances and immediately driven here. Were about an hour south or so from the entrance to that cave. Were in a more populated area of chiang rai province. And inside that hospital, thats where those boys are being treated right now. In terms of their condition right now, joe, we dont know exactly. Thats what were trying to figure out from officials here. But given that they were able to make that treacherous journey that jonathan just described, you have to figure, theyre at least in somewhat decent physical shape. But that said, the preparations that were under way here at the hospital were extensive. Earlier in the day today, cnn witnessed a little bit of those preparations, watching gurneys be laid out outside of the emergency room here, and actually earlier, when i was up at the cave entrance this morning, we saw all 13 ambulances actually take their place outside of the cave entrance before we were forced to leave that area. So clearly, doctors, nurses, medical personnel, they were prepared for this possibility, and joe, i say possibility here, because there was nothing guaranteed about this. 16 hours ago, we were saying that there might be a chance or there was a chance that none of the boys would be able to make it out safely, because thats how dangerous this rescue attempt was. So the fact that we are talking about four boys safely inside this hospital right now is really miraculous, and a testament to the skill and expertise of those divers doing their best to save this soccer team, some of whom remain trapped in that cave. Any sense about how forthcoming the hospital or the doctors might be eventually . Whether anyone has discussed a news conference, you know, here in the United States there are so many concerns about the privacy of people who are being treated for medical conditions. Any sense that were going to hear about the shape theyre in, whether dehydration, for example, was a factor, returning to solid food, things like that . Reporter yeah, joe, its kind of two stories here. On the one hand, thai officials have been forthcoming with fwhfgs, more so over the last couple of days. We really saw a shift in their media access that they were giving us earlier today when it became apparent that this rescue operation was going to go forward. You know, earlier today, we could have walked right up to that hospital and yet when they were bringing the boys in, they had completely blocked that road behind us, and theres actually some green netting up outside of the emergency room right now, so no prying eyes could actually see those boys being taken into the hospital. Theyre being given the privacy that, frankly, they deserve. So in terms of how forthcoming authorities will be, we are expecting them to give us information. The public, they know, is clearly interested in whats going on here. This entire country is riveted, if not the entire world is riveted by this story. Clearly authorities are taking the necessary and deserved steps to make sure that these families as they reunite with these four boys have the privacy that they need to hopefully heal from this traumatic experience. Matt rivers, thanks so much for that. The authorities there literally and figuratively closing the net on access and quite understandable, as well. Thanks so much for that. This rescue is both physically and emotionally exhausting for everyone involved. Lets bring in jennifer wild, clinical psychologist at Oxford University and expert in post Traumatic Stress disorder. Let me get your thoughts on this. Can you give us some idea what it was like for those boys in the minutes and hours after a rescue like this is completed, and successfully . So the boys will be the four boys that are out will be feeling relieved and excited to soon be with their families. Of course, theyre not going to be thinking so much now about the time in the cave, but actually just recovering from having been in there. But they will be thinking about their friends who they have left behind, and hoping theyll be able to get out safely. Of course, they know firsthand how difficult it was to get out, and it was an extremely long mission to get them out. So in terms of their emotional resilience, what is going to be helpful is for them to focus on the fact that they are out and how to move forward and the offers that have come forward, so they have been offered to join fifa in russia, to really looking forward to that. Of course, theyre going to feel anxious about the boys who have been left behind, and, you know, there is a risk of survivors guilt if anything goes wrong, and the rest of the rescue mission. Its still a very, very tender time. Right. And now lets try to if we can, a little bit inside the heads of the boys who are still inside the cave with the coach and waiting to make that dangerous journey out. We just talked a couple minutes ago about whether they even know those four have made it to safety. So could you talk a bit about what its like for them waiting and wondering when the next help will arrive . So its very anxietyprovoking in that state, waiting to be rescued and not knowing if the rescue operation is successful. So they know that the four boys have been taken out. They dont know if they have survived. They dont know the extent of treachery that lies ahead of them. They have an enormous amount of support and expertise around them, having two divers. So thats very positive and will be reassuring to them. But, of course, they have to spend another night in the cave or another several hours in the cave. And presumably there will be a number of boys who are taken out next, and it may not be all eight all at once with the coach. It will have to be broken up, i would expect, which just increases anxiety. So its the uncertainty. But what is going to be really helpful in that situation is to focus on the fact that they there is a rescue operation in place. Theyre likely to get out. As long as they can follow the instructions of the divers who are helping them, and as long as they can stay calm. So the point in the mission that are most difficult are the narrowest points. And thats usually the area that is really the most frightening, and increases the sense of claustrophobia. And those are the more danger points in terms of anxiety and panic. So we would want them to stay calm and just really focus on the fact focus on what the divers are doing and communicating with them to get them out safely. So now lets talk a little bit about your expertise there. The Traumatic Stress piece, if you will. We do know that oftentimes in the United States, you talk about ptsd in terms of people in the battlefield or people who have experienced explosions or whatever and lived through that. Loud noises. This seems to be very different, in that its probably not associated with loud noises, or violence, if you will. But ptsd, nonetheless. Yeah, so this would count as what we call a criteriian a event. There was harm to their life, and for a period of two weeks, they didnt know if there was a potential of getting out safely. So that definitely would count for a traumatic event. And there will be reminders when theyre out. I mean, there are a whole host of situations that might remind them of this event. So it could be being in water, be it swimming. It could be being in an enclosed room with a door closed, that might bring back feelings of being trapped again. It could be being in darkness, nighttime. There are many, many potential different reminders. Most people who go through a trauma dont develop ptsd, so its not a fact theyre all going to develop post Traumatic Stress. They might not. In the first month after a trauma like this, its very normal to have unwanted memories and feelings that are very similar to what you experience during the event. So if they felt panicked and anxious during time in the cave, that is common and the aftermath in the first month after a trauma. Normally this dies down during time. Thats typically what we see in people. But if they have flashbacks and unwanted memories and feel scared, we would want to intervene quite quickly with a short term psychological therapy such as trauma focus, cognitive behavioral therapy. And potentially the most stressful part of this is yet to come, that journey back to safety, if you will, through that labyrinth of tunnels there in thailand. Thank you, jennifer wild. Stay with us now. When we come back, were going to take a closer look at the layout of the cave system, and the difficult conditions rescuers are going to face in the hours ahead. How can we say when you book direct at choicehotels. Com you always get the lowest price on our rooms, guaranteed . Lets say it in a really low voice. Carl . Lowest price, guaranteed. Just stick with badda book. Badda boom. Book now at choicehotels. Com come fly with me, lets fly, lets fly away. You shouldnt be rushed into booking a hotel. 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Joe, the initial part of this went faster than officials expected there. They were able to get two boys out about ten minutes apart and ten minutes later, two more came out, ten minutes apart. Very promising news. The only way this is possible is because there was a massive effort to pump out endless gallons of water down there to make some room for these boys to get out there. On top of which, even then there were areas that remained submerged. So divers had to put these full face masks on the boys and then in the actual process of bringing them out, they would have one diver up front who would have a line going back to that face mask. He was carrying the air supply. Another line securing the boy. Theyre on a tether all the way through the tunnel to follow things through and then another diver coming up behind to make sure that he was secured both front and back, joe. All right. So tom, i know we only have limited maps of what the situation looks like there underground. But do we have a sense of how far they actually traveled this way . Its very sketchy exactly how much distance is involved. Some have it like 100 yards or so. Others much more. In one account out there, still a quarter of the cave is filled with water. If that is true, that means whether it was one stretch or spread out, these boys had to go the length of 11 football fields under water, sometimes in very, very tight quarters, muddy. They can barely see. A very difficult thing to get done. And yet they did manage to get from that group over there four of them over here. And then as you noted earlier, they had to stop, because the oxygen has to be replenished. But this absolutely is such a race against time at this point, because think about the rains. As we noted a short while ago, what they have been clearing, what has made part of the cave passable is getting rid of this rain, which happened from the time the boys disappeared to around the time they were found. They have had sort of a lull here, but now the rains are coming back in earnest, as you would expect in the monsoon season, and that could very quickly reduce and eliminate all the advantages that they have fought so hard to win there. Thats why theyre watching the clock and saying as hard as this is, they have to press forward quickly. Joe . So many factors there, tom foreman. Thanks for that. Youve got psychology, typography, how much air. And even the question of current with the water. A lot of questions they have to deal with. Four boys have now been taken out of that cave, with the help of thai navy s. E. A. L. Divers. But they also used all of their oxygen to do it, and now must refill the tanks before they can get the remaining eight. So joining me now is former navy s. E. A. L. , jake zwig. Officials say the rescue of these boys took about ten minutes less than they had practiced. Pretty good sign . Yeah, that means they got it pegged, exactly what they have to do to get them out. I mean, thats always a great sign, when you rehearse something and then you do it for real in exactly the same time. Now, one of the things, jake, and i think you know this too, just as a diver, they say on the way in, it was supposed to take about six hours. On the way out, about five hours. Part of the thing i wonder about is whether some of that has to do with current. Theres been a lot of talk about strong current of the water. And presumably, if going back the current is pushing them and they can kind of drift dive, it would speed them up. But current can be a huge problem when youre dealing with darkness like this, right . Very much. So you have to believe that the current is running out of the cave, because most caves are downhill. Theyre formed by water running out of the cave in the first place. So that would make sense that theyre fighting time going against the current. And then once they get the boys, even though theyre going a little bit slower with them, the current is helping them along. And theyre on a guide rope. So, you know, maybe one of those situations where theyre really able to coast most of the way. Right. Can i show that graphic that we have, tom foreman used just a couple minutes ago . We have a pretty good graphic that sort of gives you there it is. So you have this is buddy dive on steroids, right . You have one expert