Its pretty early in the game and I can't remember where exactly it takes place but the big room you enter with the woman trying to hack the door. Later you come back to that room through a peripheral entry and there are people dicking around including a woman with a shotty right as you exit. My first trip out I got blasted, so I reloaded and threw a noisemaker in the room. The Alien proceeds to kill everyone while I lay low in the room that you exit from.
When I come out I count the bodies of the dead but don't see the woman anywhere. I remember where she was at on the second level and go back to see if she's alive or dead.
I see blood, then splotches of blood, and then the blood trail ends, directly under a vent.
I have no idea if the body glitched and just disappeared or if CA wanted to imply that the Alien was dragging human npc's into the vent but it was a nice touch if they did.