Harry thought he'd better stay out of it from here on, but at least he could say he tried? It didn't look like there was much to stay out of though after Hermione yelled at the both of them and then exited the room.
He hadn't expected Ron to be stupid enough to try and follow her, but apparently he was and Harry put a stop to any attempts he made to even sit up. "Don't be an idiot," he told him. "You open up one of those cuts and you won't even get a chance to bleed to death before she kills you."
He looked towards the door and then back at Ron. "I'll go. You stay here. Not moving."