Here it goes!
3 seconds sound clip from the X Minus 1 - A Gun for Dinosaur by L. Sprague de Camp classic radio drama series.
You can hear this line at 00:26:02 in the radio play.
Quote context
[...]
- No, it's too late. The chamber's in transition now.
- Look, hadn't you better get out of here before he kills you?
- Well, it's been quite a world up to this point, eh?
- The time chamber. It's back. We'd better get it open.
- Good Lord, look at that. Ghastly, isn't it?
[...]