http://www.cracked.com/article_20871_6-things-movies-dont-show-you-about-life-submarine.html/
The oxygen levels on a submarine are kept dramatically low. This is primarily to keep the risk of fires at a minimum, but it has some side effects. Most submariners work with their hands and get injured a fair amount. You'd be surprised what a small drop in oxygen levels will do to your body's ability to repair itself. Constantly oozing wounds are the name of the game. It is not a fun game.
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The Navy doesn't want you to quit, so when someone does wash out, it's treated like a dereliction of duty. "How dare you betray your classmates -- nay, your country -- by wanting to live on the surface world? You don't want to be a Morlock, son? What, so a giant metal group coffin isn't good enough for you anymore?"
The oxygen levels on a submarine are kept dramatically low. This is primarily to keep the risk of fires at a minimum, but it has some side effects. Most submariners work with their hands and get injured a fair amount. You'd be surprised what a small drop in oxygen levels will do to your body's ability to repair itself. Constantly oozing wounds are the name of the game. It is not a fun game.
--
The Navy doesn't want you to quit, so when someone does wash out, it's treated like a dereliction of duty. "How dare you betray your classmates -- nay, your country -- by wanting to live on the surface world? You don't want to be a Morlock, son? What, so a giant metal group coffin isn't good enough for you anymore?"

