Hidden rooms in The Sims 3 Late Night?

My sim was in the cemetery and he went into a building with stairs. The stairs led underground and there is a vampires layer. I tried waiting for the vampire to come to his home but he never came. Does a vampire live there? Also I think I was in one of the bars and somehow I ended up in a place with two coffins. Are there any other hidden rooms? Does anyone live in the hidden rooms?