Szell: Is it safe?

Babe: Is what safe?

Szell: Is it safe?

Babe: Tell me what the "it" refers to.

Szell: Is it safe?

Babe: I don't know what you mean. I can't tell you something's safe or not, unless I know specifically what you're talking about.

Szell: Is it safe?

Babe: Look, I told you I can't... [Szell stabs the probe into the nerve] AAH! AAAH! Aah!

…

Szell: Is it safe?

Babe: No. It's not safe, it's... very dangerous, be careful.

Marathon Man (1976) (Slightly re-ordered)