[piasa]

" Granted, I am not a diving expert, but it seems to me, a few anchors, some rope/cable, and a few diving helmets, and you could have those kids out in an hour."

You're right, you're not a diviing expert... didn't even dive very deep into the article: :-)

Gary Mitchell, the group's assistant vice chairman, said getting out of the cave requires about a kilometer (half a mile) of diving total, though not all in one stretch, and takes about three hours.

[Kelyan]

No, I read it. Did you read this part you quoted?
>>though not all in one stretch
Thus, there could easily be rest/resupply on the trip. Maybe there are issues I’m not seeing. This seems like a solvable problem though.