"Hey - what -" Chase doesn't take kindly to being pushed off to the side, but when Castiel speaks, he doesn't hesitate for a moment. There are a few basics he's managed to keep glued to his memory on a day-to-day basis without having to read note cards:
1) House is an angel 2) Thirteen is a demon 3) Never, ever speak with Keats 4) Listen to Castiel
That last one, well, it was more like "listen to Castiel when it seemed important" and this Chase could classify as important. "What's wrong?"