Lot of concern. and just briefly, how long would it take theoretically to to actually drill another entry way, an exit, if you will? reporter: they would have to find it first. there have been hundreds of people walking in the hills and the forests around here. there have been helicopters that have been brought in. they ve been using drones. they ve been trying to evaluate the landscape to see if there s anywhere that presents an opportunity, a crack, an access to a chimney, a place where they could drill, somewhere they might be able to drop ropes and pull the boys out. this in the opinion of a lot of the divers i ve talked to in the last several days, would be the safest option. it s not at this point the most realistic, it s not the easiest, but it would be the safest, to bring the kids out, because they would be surrounded by air and not by water. the concern is less about teaching the kids how to swim. ....