did they actually really do that or was it set up? either way this may be a really dumb question.
Not dumb at all. They shot video in several caves, then intermixed it with video of the surface team "following" the divers. The big problem with that is it takes a couple of minutes to locate a transmitter, and the transmitter has to be level for it to work. It made for a more interesting story, than them stopping every few hundred feet and waiting for the surface team to locate the transmitter. The restaurant scene was shot in a Sonny's BBQ near a cave, but there was no real passage under it. There is a cave under a golf course, but it has low visibility, so I don't think they used any video from there.
Forrest Wilson (with 2 Rs)
Any opinions are personal. Sump Divers