Mimi was gone, the bomb was dropped on Victor as soon as he woke. At first, he thought she was abducted or something, like Draco taking her away to punish her for punching her.
But when he saw the pillow he was currently hugging, Victor knew she was fine. She obviously went through a great effort not to wake him. And for some reason, that pissed him off.
Mimi should have waited for him to awake, it was not like she had a job to attend to - he was her job, her teacher. He could easily decide to give her the whole day off.
Or she could have woken him up. And then do what?
Well, they would have breakfast together and he could take her home. What if something happens to her on the way? With him around, he would protect her.
[A/N: well, nothing's happened to her on the way throughout her twenty-three years of existence until you arrived]
