Don't. Stop. You'd never survive.
4 seconds sound clip from the Forbidden Planet (1956) movie soundboard.
You can hear this line at 00:57:08 in the Blu-ray version of the movie.
Quote context
[...]
- Now, doctor, you can read it here.
- Well, there's something wrong here. I have an IQ of 161, yet I don't register a third what you did.
- It's all right, sir. A commanding officer doesn't need brains. Just a good loud voice, huh?
- How do I make an image? Do I just pull this switch here?
- Don't. Stop. You'd never survive.
- Our Belerephon skipper tried it and it was instantly fatal to him.
- Oh, I see. So you're immune to this too?
- Afterwards, I lay unconscious for a day and a night.
- And yet you came back for a second go at it.
[...]