A few questions (SPOILERS)
First, I did enjoy the film, thought it quite good, so not picking.
1. There was talk about these divers being hung out to dry by the private company they were employed by. Rescue was from a US Naval vessel on the word of a Chinese fishing boat. Did anyone else not think this plot thread was going to be expanded on with the divers threatening to cut oil lines and cause billions of $ of damage unless rescued?
2. I might have this wrong, but why didn't the final 2 divers simply inflate anything (loose clothing etc.) to raise them to the surface MUCH faster? I understand a little of the risk of the bends/nitrogen poisoning from fast decompression, but if anything this would have made them unable to swim and require some buoyancy?
3. Wouldn't the last 2 divers at least have tried buddy breathing and body contact (shared body heat) to the length of the umbilical - then used flotation to assist the final section to the surface?