They know what's going on down here.
2 seconds sound clip from the Robot Monster (1953) movie soundboard.
You can hear this line at 00:27:30.972 in the Blu-ray version of the movie.
Quote context
[...]
- Well, that may prevent Ro-Man from finding us and blowing us up...
- But against the sweep of the death ray, it's powerless.
- No, the serum, that's the thing.
- Couldn't you find any more in the lab? Plenty.
- Why?
- Does the garrison know you're coming?
- Well, how could I tell them without letting Ro-Man know too?
- They know what's going on down here.
- They'll figure it's Ro-Man and blast the ship right out of the sky.
- We'll have to get word to the space platform, that's all.
- Jason and McCloud take off in two days.
- On foot, it would take me longer than that to get back there.
[...]