At the depth the characters are, experts suggest there would be less than 15 minutes of air for them. See more

Goofs

One of the divers in the cage attempts to show the rescue diver where they are by banging on the cage. Human ears determine direction by measuring the difference in the time it takes for sound to reach both ears. Due to the increased density of water vs air, sound travels at a different speed and human ears cannot determine direction underwater. Divers are trained to know this, but it is possible that the divers were panicked and not thinking correctly. See more