Ron doesn't yell when he opens the door and there's an Inferius there, swaying back and forth on rotted feet, bony hands already reaching up to grasp at him, dead white eyes staring.
Harry yells, and Hermione utters a strangled little 'meep' but Ron doesn't move. In one second of tangled, incoherent thought, Harry thinks that Ron is frozen with shock and he's lifting his own wand to try and aim around his friend when Ron comes to life and dives at the dead thing, rather than away from it, and Harry remembers. Ron doesn't have his wand.
It's all over quickly. The Inferius flails mindlessly, grasping, snapping at him with broken, rotted teeth, its hands digging bloody furrows in his freckled arms but Ron is heavy and quick and alive, and not really that stupid. It's only a few seconds before he has the squirming thing twisted around, facing away from him and holding it tightly by the arms.
"Kill it, Harry," he says, quietly, they can't afford to yell and be found by whatever might have sent it and they're running out of hiding places. "Set it on fire." So Harry does.
"I should have clarified," Ron says much later, his hands and chest still covered with the orange foamy stuff that Hermione conjured up. They didn't have to take his shirt off to treat him, as most of it was burned away. "When I said 'set it on fire' I meant the Inferius, not me."
Harry snorts in spite of himself. "If you hadn't been hanging on to the bloody thing, it wouldn't have been a problem. Why'd you tackle it, anyway? I could have got it from where I was."
It's only then that he realizes that Ron is flushed, and has been since Hermione left to bury the pitiful remains. Probably before, too, but they were both too busy flipping frantically through Hermione's spell books to find a cure for the burns to notice.
"Dunno," Ron says, and turns a shade redder. The angry purple-ish blisters have mostly faded from his chest, but his hands are still swollen and painful looking. When Ron turns red like this, the flush creeps down his neck and stops around his collarbones. Harry, who has always been privately amused by this phenomenon, doesn't say anything, just raises an eyebrow.
Ron rolls his eyes. "Do you think I don't know you've been practicing that look? Knock it off, you look deformed."
"Why'd you tackle it?" Harry repeats.
"I just told you I don't know. It just seemed like the right thing to do."
"It was dead."
"Yes, Harry, I know," says Ron with exaggerated patience.
"I'm just saying, you know, that as a general rule it doesn't make a great deal of sense to tackle a walking corpse when there are two perfectly competent people with wands standing right behind you."
Ron chokes, and Harry's about to drop it and ask if he's okay when he realizes that Ron is laughing.
"Harry," he says when he finally stops, "you would have done exactly the same thing."