Looks to me like the victim was complacent, and just assumed nothing bad would ever happen, because it never had before in her experience.
I can’t see in the Daily News article where it said she left the door ajar. Perhaps the News was being too polite to get into that. But I just noticed she lives in the Lincoln Center area - nice area although of course creeps are everywhere. For some reason, I assumed it was one of the big new buildings on the west side/mid town area.
The doorman really did not do his job that night.