[it would probably be a surprise to Narvin to learn that, at least in part, he has the Doctor to thank for this "luck"--though it's also due to Menzies' nature and the fact that she assumes she would be harder to double-cross while invincible]

No, I made it up. [the statement is clearly sarcastic. but at his new option, she shakes her head. there are limits to how far she's willing to trust him--not that she's going to say it like that if she doesn't have to, of course] Ah, no. I'd rather not bring a Time Lord into the middle of a crime scene if it's all the same to you. So...? [she waits expectantly for his decision]