Good thing I viewed this page before posting. I caught a couple of typos. Falanorians are the ones behind the classic UFO abduction scenario so they can control stuff just with their brain. Such high technology it is akin to magic. The Falasnorian domination is inhabiting another body and using them as a puppet. In the abduction scenario this was usually done with their little Gray robots. Classically the little Grays were the robots mindlessly controlled by the big Grays or actually light blue Falasnorians. This is often remarked upon in abduction accounts. The little Grays are robot servants of the tall ones. Da-tu doesn't have any short ones so she decides to use Dr. Rush as her unwilling surrogate instead. Now why doesn't Da-tu just do that to the whole crew? She actually is as far as she needs to. She sees and senses through everyone she controls. But with so many she couldn't control completely and supress their own personality at the same time.
And here's Vera back from setting up the other ship.