I love this show but this was a very poorly done episode in relationship to how things are in reality. One thing that is accurate, a sub skipper is God. Then the problems begin. Subs do not leave on a moments notice, and they do not dive immediately, they are in shallow water. Also before getting under way there are countless announcements over the loud speaker.
They did not even begin to get into the phobias he could have on a sub. The communal bathroom is one that you could do a scene on.
Then the ballast tank, which are not open to the inside of the sub, if they were, going into one you would smell the algae and the stench of the water that never gets blown out and the bacteria gets a chance to feed. It would not be a pleasant smell. Then there would be no lights inside.
Also this episode was without Leyland, where was he.