Policemen running. What else?
Look at the Alien shots. In both of these shots, multiple things are shown at the same time. In the ones with the body on the left, you have two conversations simultaneously going on, one in the foreground right between two people about to examine the body, and one between another group who's in deep background. You've got the dead body in the shot because it helps to build tension (it has an alien in it, remember?). You've got the stressed out people in the background who don't know what the fuck is gonna happen, and you've got the two "scientists" in the front.
The other shot has the alien in the foreground, the genuine terror in the faces of the two people in the background, again the dead body on the right side of the screen, a constant reminder, you've got a similar "doorway" composition (repeated everywhere in Alien, from set design to shot composition), you've got the guy on the left to watch for because he's going to try and manipulate the alien...
That's a lot more information than just "COPS RUNNING SCARED".