have you seen the movie “turistas“? (if not, it’s the horror movie
where good-looking young americans go to a latin american country for some R & R and end up being chased and captured so that their organs can be harvested.)

toward the end there’s a chase/fight scene that takes place in
underwater subterranean caves.

aside fr the fact that underwater scenes like these are always much more well-lighted than they should be, I was wondering how realistic the scenes were where the characters are swimming from one pocket of air to another.

we’ve all seen these kinds of scenes (in titanic, poseidon, etc). What “turistas” brings to the table is that some of the pockets of air are literally as small as pancakes and the characters can only just get their lips into them, and when they inhale, they inhale up the entire air pocket.

when I saw these shots I was impressed. I assume the shots are
computer generated, else you’d have the actors continually choking on water.

but I was wondering if this is possible to do in real life?

and if it is, what is the likely composition of those air pockets?
could they be composed of air that would knock a person out?