Peter usually comes to check in on Bonnie daily. They either hang out or he makes sure she's not studying the magic stuff too deeply, and so it's not really out of the ordinary that Peter opens the door after one knock to signal that he's coming inside except it's not Bonnie that greets him so quickly that Peter's nearly knocked back by it.

"...Damon? Where's--"

And he stares at him abruptly, smelling the booze coming off of him, smelling... blood too. His mouth parts, and panic hits him immediately, intensely, completely. He tries to push past him before the words even come out, but Damon reaches out a hand to stop him immediately and now it's about time for two super strength people to shove at each other until one of them moves, an immovable object verses an unstoppable force, because-

Something must have happened. It's radiating off of Damon like- Something happened, and he is in Bonnie's room, and Peter can smell blood. Panic starts to beat in his rib cage like it's its own beast inside of him.

And he knows what Bonnie's mirror said about her, and he knows how dangerous it could all be-- His voice is shaky in denial already, yelling, hands grown to fists ready to hit him.

"Let me through!"

But Damon's quicker.