Well, I give up.
3 seconds sound clip from the Meet John Doe (1941) movie soundboard.
You can hear this line at 01:55:32 in the DVD version of the movie.
Quote context
[...]
- No sense going up there. I been here for hours. He ain't here.
- That's crazy. It's 14 floors.
- It's as far as the elevator goes. We gotta walk up to the tower.
- I don't know what gave us the idea that he'd attempt anything like this.
- I guess you're right. I'm afraid the joke's on us.
- Let's go. I hope nobody finds out we've been here.
- I wouldn't do that if I were you, John...
[...]