The Doctor and Count Scarlioni/Scaroth in “City of Death”

Now Count, this is what I've come to say. If you're thinking of going back in time, you better forget it.

Now why do you say that?

Well, because I'm going to stop you.

Oh no, on the contrary, Doctor. You're going to help me.

I am?

You are, indeed. And if you do not, it'll be so much the worse for you, for this young lady, and for thousands of other people I could mention if I happened to have the Paris telephone directory on my person.

Count, that sort of blackmail won't work, because I know what the consequences will be if you get what you wanted. I can't let you fool about with time.

What else do you ever do?

[caught out] ...Ah, well, I'm a professional; I know what I'm doing.