I did some changes on texturing the rooms / corridors. I split every room into smaller objects: floor, walls and ceiling. Now i can get higher-res textures for every part and do decal/dirt texturing because i can go without using overlapping uv's. And also concentrate doing just floor tiles for floor texture for example, no need for fitting wall textures alongside floors etc.. it's just simpler.
I can also use one texture for multiple objects in this way..
All the unwrapping (of rooms / corridors) is more or less complete now.