Living Doll - S5-E6
Visible crew/equipment: The boom mike shadow is visible above Annabelle, after she tells Christie that Linda is at the door.
Living Doll - S5-E6
Visible crew/equipment: When Talky Tina calls Erich, the camera zooms in as Erich starts talking - and its shadow appears on his arm.
Stopover in a Quiet Town - S5-E30
Visible crew/equipment: After Bob and Millie realise the tree and the grass aren't real, when they head towards the town Bob calls out, "Hey! Hey, anybody here?" Then Millie adds, "Somebody," and the shadow of the boom pole/mic moves across the bottom of the screen. (00:14:55)
Stopover in a Quiet Town - S5-E30
Visible crew/equipment: When the camera pans to Rod Serling for his opening narration, you can very briefly see several crewmembers and some backstage equipment.
Answer: It's explained in the episode. The aliens are experimenting to see how humans react to various scenarios. This just happens to involve them using super strength.
Thanks. It's been a long time since I saw the episode so I forgot.