She wanted to hurt him. Hurt him bad. But she knew that his heart would forgive. So she hurt his mind. The mind that doesn't forgive. It remembers, for a very long time. And that's what she wanted. For him to remember always. What it means to get hurt, experience pain inside the brain, all the time. This would ensure that he never ever forgets her. The heart was weak, it always had room for forgiveness. But the mind did not.