I like that it has a full size lathe (how common is that for subs?). Well and a swimming pool, seltzer water dispenser and the 1980 Soviet sub arcade. I remember that was my favorite arcade game too.
Machine shops aren't uncommon on naval ships. Such a well supplied one is perhaps unlikely aboard a submarine, but missile subs are the largest and generally the longest-cruising of any type, so it makes a deal of sense they'd have as much capability for self-maintenance as possible, especially given their vital deterrent role. Same goes for the pool et cetera - the human crew being as important to the mission as the boat herself, and just as much meriting maintenance.