"If I'd known you were liable to pull a knife on him, I would've," Kay says shortly. Donatello can't help being a turtle; she's not about to draw unwarranted attention to the fact that he is. That'd just be rude.

Of course, now that the 'pretend he's not a mutant turtle' plan has backfired entirely, she has to take a different tack. Say something to try and smooth things over and change the subject as quickly as possible. "Probably should've mentioned it. Come in, Donatello, it's good to see you."