Careful.
3 seconds sound clip from the X Minus 1 - Mars is Heaven by Ray Bradbury classic radio dramaseries.
You can hear this line at 00:24:14 in the radio play.
Quote context
[...]
- It's a perfect trap, Captain.
- Who would suspect his own mother? His grandparents?
- How easy. Just a knife in the heart of each sleeping man.
- That's impossible, but we've got to get back to the ship.
- Careful.
- Ed. We, uh, we wanted a drink of water, that's, that's all Ed.
- You're not thirsty, John. You don't want a drink. You don't want a drink!
- His face! It's changing. He's a Martian!
- Run!
[...]