*Shrugs* She was doing to much by following him, but that's better than calling the cops on him. I know everyone's assuming she only treated him like that because he's black, and ya'll might be right considering the ways of the world. That said, she was pretty much doing what she's supposed to do. At least initially. You're not supposed to let people you don't know into the building. That pretty much defeats the purpose of having that kind of security.
I'm guessing he didn't have his keyfob or whatever because I don't understand all that back and forth with the chick at the beginning when he could have told her to back her ass up, let the door close, let himself in, and been on his way without any of that nonsense.