"No. You can't." Zeke took a step back. It wasn't a retreat, it was knowing hw wasn't wanted there. He should have kept his mouth shut, and left before either of them saw him. Crowley might have sensed his presence, but he could have been anywhere nearby, to be sensed.
Too late now. He'd revealed himself, let them know he'd seen them. "I'll be in my library, when you're done playing house." It was a cheap shot, and probably didn't pack as much punch as he'd hoped.