from these other valves and ultimately they will shut down the oil from all the valves in this new cap they've put on. one of the concerns that the government scientists raise, that when they do that, the goal is to build up the pressure and stop it, they're worried some could come out down here, where the seal where the new cap was put on, some pressure could come out there. that's one concern. the bigger concern i was told today by people involved in this is this, that if you cap it here, the pressure comes down, and you'll get down here at the base of the well, this is the old well essentially that down here, right along the seabed floor, there could be problems. and if that happens, they're worried about some sort of catastrophic rupture down here. walk us through the big questions here. >> well, this thing -- thank you, john. the thing exploded. 86 days ago. 11 people were killed. and you don't know what sort of shockwaves, what sort of pressure waves went up and down this long drill string, the riser and so on.