Katrina is aghast by Aaron's words. "No, I won't! I won't!"
In all honesty, Katrina doesn't know if she will get back together with Marcellus if he threatens to hurt himself. But she knows that he is not that kind of person, he won't force her that way. She trusts that he wouldn't manipulate her like that.
Katrina has no intention of getting back together with Marcellus. It won't happen just because they meet in person. Aaron is thinking too much.
All of a sudden, Katrina realizes that something is wrong with Aaron's questioning. She looks up defiantly at him and says, "I'll meet whoever I want! What I do is none of your business! I hope this will make you realize that I have my own life,"
After living under Aaron's oppressiveness for so long, Katrina immediately felt guilty for her actions and listened to him when he started interrogating for no reason. She felt bad the way Aaron treated her right now. She still didn't forget what he had done to her back in his villa.