After Robot B-9 deactivates Raddion, Major West removes the transpirator image plates and destroys them by crushing them in his hands and then stepping on them. In the next scene, the remnants of the plates are no longer on the ground where they were a second earlier.
The title of this episode is somewhat misleading, as there are no dreams, and no monsters , since Raddion is an android, and not a " monster " by LIS standards.
After Dr. Smith and Major West escape from the manacles by throwing a stool at Raddion, they run through the arch into the room where Sesmar is sleeping When Dr. Smith and Major West run into that room under the arch, Raddion's foot is visible behind them for a second until he moves it back behind the wall, long enough for West to take the remote from Sesmar.