Dean moved quickly, too quickly and Castiel did the only thing he could in the circumstances, moving fast to brush his fingers over Dean's head, sending him to sleep. He caught the older Winchester brother before he could hit the floor, easing him down more gently with a murmured "sorry. I'm so sorry."
He made sure Dean was breathing comfortably before he stood up, his expression calm, even as his mind raced.
"I am protecting them," he spoke to Claire first, his voice soft. "Sam will not cope if we kill Ruby right now, right here. We do that, we will lose him for good. He has too much darkness in him now, we need to purge it from him and it won't be as simple as merely depriving him of the source, he needs to want it." He spoke as though neither Sam nor Ruby were even in the room, these words were for Claire and John alone. They were the ones that mattered.
Then, for the first time since his arrival, he spoke to Sam, his face filled with a cold fury.
"Do not think to order me to do anything ever again," there was a rumble of thunder as the angel's wrath grew. "I am fighting every instinct I have not to smite you down where you stand this instant, do not push me." His wings unfurled, black feathers reaching out to the sky. For too long many had treated him as though he was one of them. A human. He was far from that.
"And you," he looked over to Ruby, with a glare that spoke of his anger, betrayal and crushing disappointment. "Do not speak again. I gave you a chance, I believed in you and you have just disrespected everything I am. I should have stood by my original belief, that a demon like you is incapable of love. It was my mistake. I don't spare your life for you, but for him. For them."