It sets him off again, letting out a grief-filled sob that fills up his throat. He doesn't know what to do otherwise and he just clings a little tighter to Sirius, fearful of what will happen if he doesn't manage to get things properly under control. What if this is the beginning of the end, as his senses get away from him and he becomes the very thing he's scared of the most? "Just don't let me hurt anyone," he says. "I don't want to go, but you have to stop me from hurting people."