i tapped out the moment I saw the scene where they start having conversation while diving........ I mean first of all, they clearly weren't talking so the dialogue they're having while underwater literally takes you out of the movie.
Secondly, that's just lazy approach to filmmaking. you can literally develop hand signals and emphasize on their expression or maybe go nuts with the sound design... but no, they took the easiest way out let's just record them dialogues and put it in when the shots clearly shows they're not talking at all.