To get to the basement where the car that would take them away was waiting, they had to use an elevator and Hailee saw this as an opportunity for her to escape.
Now or never.
Because if they managed to take her, Hailee didn't know what Giana would do to her and she didn't even want to guess about it.
By just seeing how Giana looked at her with such hostility and hatred, Hailee realized that she would be in even greater danger once they succeeded in their plan.
Therefore, with great force, Hailee bit the ear of the man who was holding her, so hard that she could hear the man's screams full of pain echoing through the walls of the house and making her ears ring painfully.
