I don't think anybody could keep from screaming if they were really terrified.
7 seconds sound clip from the The Tingler (1959) movie soundboard.
You can hear this line at 00:41:42 in the Blu-ray version of the movie.
Quote context
[...]
- Mustn't scream. I mustn't scream!
- I broke down and screamed, didn't I? I couldn't help it, Dave.
- Things were pretty foggy, but I remember thinking that I mustn't scream.
- But the pain and the fear were so great.
- I don't think anybody could keep from screaming if they were really terrified.
- I'd better be on my way. Good night, kids.
- Suppose a person could not possibly scream?
[...]