Janeway
I don't think he knows anything. And I think he knows too much.
Szell
You can afford to think what you wish. I can't.
...
Szell
[to Babe]
Oh please don't worry. I'm not going into that cavity. That nerve's already dying. A live, freshly-cut nerve is infinitely more sensitive. So I'll just drill into a healthy tooth until I reach the pulp... unless of course you can tell me that it's safe.

