As a sub-sea diver you could be working inshore or offshore. Initially, to gain experience, you may be doing less paying inshore jobs, but once you have done that, you graduate to lucrative offshore jobs.
Thinking ability reduces once you are deep down under water. Divers have to be a tad smarter than others to counter this disadvantage.
Sometimes you work at the end of your physical endurance. That separates the boys from the men.
Your voice changes the deeper you go into the water - it becomes squeaky and you sound like a cartoon character.
The technology used in deep-sea diving and space exploration is quite similar.