The only way in is to speak to an attendant inside the building via an intercom system near the entrance to the walls surrounding the tower. Tenpenny Tower is a residence for many, but it's also a well-fortified fortress that protects itself effectively from the outside world. You could kill the humans to let the Ghouls in, or vice-versa. There are other ways to do this side quest. We went with a more neutral/good karma approach, trying to get the snooty human elements out of Tenpenny so that the Ghouls could move in. Please keep in mind that we've written a very specific way of getting through this side quest.
