It's Snape's fault, and always will be. It's easy to foist blame onto him, nasty and vile and cruel, in his way, even if he's sulky and clever about his cruelty. Even if maybe they were cruel first, he deserved it, and he went on to prove just how badly he deserved it as the years went on. And clearly he only grows worse, because they're here now, aren't they, with his hand aching and Snape's face now a mess of blood. They wouldn't be here if he didn't deserve this.

The hot shock of pain at his wrist jerks him out of his blind rage, and Sirius hisses, twists, tries to tug away--it means he's got to let up from hitting Snape, but it's better than having his hand burnt off. He scrambles back, wrist burning, hand aching. His breath comes ragged as he stares at Snape across the slight distance--if looks could kill never applied so well to a single stare--before he shoves away from him entirely.

"Keep away from me." It comes out a snarl; he doesn't try and couch it or correct it. His anger is still in him, just below the surface. It won't fade anytime soon, not now. "Just fucking keep away, Snape."