Hailee was really confused and upset about everything that was going on. That video had really scared her and she still didn't know why it had been sent to her.
However, Caleb had messaged her and asked her to come to this place where she would be safe. And since she trusted him and the others at the gym, she had agreed to come here.
She placed herself in a corner so that she could be out of the way, but also have the wall at her back. So far, she didn't recognize anyone so she kept watching the doors.