She crosses her heart, promising to stick a needle in her eye if she doesn't uphold her side of the bargain.

"Will be careful and quiet as a mouse. I swear, I'll do my best to make sure I won't get in trouble with anyone." There are benefits to being a ghost. Like being invisible most of the time and walls suddenly becoming new doors for her. Most vampires and werewolves can't do that, now can they?

.... If they could do, that would be rather frightening. Wait. Focus, Clara. "Where did you last see him? I can go check there to make extra sure he isn't going back there to hide. That's a place to start, I suppose."