I have no way to find out, but I speculate this was related to a quest during development. I guess it was abandoned at some point, however. The inaccessible room is tiny and contains a bed (usable), no containers, and no items. I was able to access it using tcl, but I couldn't get unlock to work on the door.
if you go into the console, select the door and use the disable command the door will disappear.