In the military, there is a hierarchical class system. Officers and NCO's (non-commissioned officers) are kept segregated from those who are above them and below them in rank. You have Other Ranks, NCO's, Staff NCO's, Junior Grade Officers, Field Grade Officers and General Officers ... something like that, I may have forgotten or mislabeled a level but you get the point. Each of these ranks lives separately from the others so that they don't have to shower with them or sit on a toilet next to someone from another rank. The reasoning behind this is that - Familiarity Breeds Contempt.
In the military, it is very important that people obey