He hadn't even realized his voice sounds snakelike - but when Remus yells he startles mid-word, staring up at him with wide eyes and genuine surprise and alarm.

He wants out. His chest is tight and he's miserable and Remus hates him and is rounding on him and there's a split second when he thinks Remus really is going to kill him and it terrifies him, honestly terrifies him, he realizes he can't deal with the thought of it—

But it's Stupefy and in that moment Regulus realizes where he truly stands in Remus' heart. He doesn't resist or even try to dodge it. Besides, the brief respite of black oblivion is better than this. When the spell hits he crumples bonelessly, sliding sideways down to rest wholly on the floor instead of half on the door.

(For now, there's nothing.)