Waking up comes hard. Part of him worries at that; he's a light sleeper, always has been, and it's never a good sign if his body refuses to wake. On the other hand, though, nothing has changed since he fell asleep. The only difference is that his room is empty now. Charlie's room. He'll be back in his cell soon; no restful sleeps there.
The doorknob rattles but the door stays shut. Is it locked for his benefit or theirs? How badly do they want to keep him in?
He never used to claustrophobic. He doesn't think he is now either. But the knob rattles and the door holds and he cannot breathe.
He needs to get rid of the fear before he returns to Azkaban.
There're people talking outside the room. Spelling the door open, or trying to. He can barely recognise them.
"SIRIUS!" Remus' shout seems to rattle the door more than the previous spell had.
Sirius cannot reply, cannot bring himself to even open his mouth. He knocks at the door instead. One-two-three, one-two-three-four, one-two. Muscle memory, it must be, because he doesn't remember the pattern.
"He's alright." Remus says loudly. "You're alright Padfoot."
He's alright. He's Padfoot. He's Padfoot and he's alright.