It's a lot to follow at once. He's still trying to process the initial situation, his mind sluggish from the fogginess of sleep and the lingering head injury. But then everything else happens, and it's too much, too fast. He doesn't know if he's even blinked more than once before things escalate.

And then Regulus is unconscious on the floor because of Remus, and there's a startled sound rather like a yelp escaping from Sirius. He forgets himself, in the moment, trying to struggle out of the hospital bed and finding himself inhibited by the sheets and his own clumsy, healing limbs. Somehow, he manages to get words out, too, though they're still fairly slurred.

"Moony, what-- the fuck?"