Regarding your security, if it looks like a crack house, it probably is, so about turn and run. If she's not the girl in the pics, run. If you don't feel at ease, or you bump into someone who makes you feel uncomfortable then bail out. All that said, being safe is one thing, but don't let paranoia get in the way of a good punt. Chances are you'll pass a guy as you walk up the stairs and more than likely he is nothing to do with the girl you are about to see.