Yes I saw that, and it was disappointing. They don't actually crawl into any vents, the xeno goes up to a hole in the wall and pushes a button to zoom the camera in, and then hops out the other side.
How do they fit in those small cubby holes? Do their long tails hang out in the hallway? Do they become invisible? What happens when two xenos try to enter the same vent from opposite ends? Are they going to tag-team the wall with their banana heads?