Her father wouldn't be there for long!
Her Master, or the man she loved and decided to devote herself to, had promised her that really soon he would be capable of dealing with him.
The only thing she needed to do was entrap her little sister for him. She had been planning to do something like that, but who would have expected that Eric would show up.
For that reason, she first needed to take care of Eric, doing everything that she could to make him break up from her little sister, and then continue with her original plan.
At first, she didn't know what to think of this guy and how to start dealing with him, but after what happened the previous day, she thought he would be easy prey.
What happened the previous night wasn't enough to make her little sister break up with him, as she would take that as a simple mistake, so she needed more.