Castiel had been on his way to the hospital when he'd sensed what was going on in the children's cancer ward, and he'd stopped to observe from afar. Senses stretched out, he watched the entire scene play out, watched the demonstration and the kids laughing, and looked into the hearts of those in the room.

Once Gil had left and the show was over, Castiel appeared in the room in a soft flutter of feathers. The children--those that notice his sudden appearance from nowhere, anyway--gasped in surprise, and he nodded slightly in greeting to them. He wasn't there to be a vengeful God, here was there to be a kind one.