The Gamesters of Triskelion - S2-E16
Visible crew/equipment: When Kirk, Uhura, and Chekov are shown their quarters all the doors open, and when the trio try to escape they are shocked by their collars, then as the camera turns toward Chekov lying on the floor a production case (#4) is visible at the left side of the screen. (00:08:50)
The Gamesters of Triskelion - S2-E16
Visible crew/equipment: When Chekov's drill thrall sits down and nuzzles up to him in his cell, the boom shadow is visible on the wall at the upper left corner of the screen. (00:14:50)
The Gamesters of Triskelion - S2-E16
Visible crew/equipment: As Ensign Haines reports to Spock, the shadow of the camera mostly shades her, then it plays over McCoy.
A Piece of the Action - S2-E17
Visible crew/equipment: After the Krako drive-by shooting, Kirk, Spock, and McCoy are forced to walk down the street, and when a woman asks about the crummy street lights, multiple chalk T-marks are visible on the ground. (00:06:20)
A Piece of the Action - S2-E17
Visible crew/equipment: When Kirk and Spock pull up after their first car ride, a boom microphone is visible in the reflection from the passenger-side spare-tire cover, which is chromed. As Spock gets out, the mic moves away.
A Piece of the Action - S2-E17
Visible crew/equipment: As Kirk comes around the front of the car in front of Krako's headquarters, another boom mic is reflected on the fender.
A Piece of the Action - S2-E17
Visible crew/equipment: As Kirk first drives the car, the camera is reflected in the car's chromed radiator.
Visible crew/equipment: While Kirk and Spock are being chased, McCoy hears the gunfire so he stands up and walks away from the rock, then just as McCoy stops to use his communicator to contact Enterprise, the ground microphone is visible at the bottom, left corner of the screen. (00:02:30)
Visible crew/equipment: When Scotty joins Thalassa while she's working, she asks if he has "prepared the megaton hydrocoils," and the shadow of the boom mic can be seen moving at the top of the screen. (00:33:20)
Visible crew/equipment: After Melakon shoots at the curtained window and kills John Gill in the broadcast booth, Isak shoots Melakon, then when Eneg stops the soldier who points his gun at Isak, the shadow of the boom mic dips into view at the top, left side of the screen. (00:45:50)
Visible crew/equipment: After Kirk and Tracey have fought, Sulu and two others beam down armed with phasers, and when Kirk tells Leslie to free McCoy and Spock, two white tape marks are visible on the floor in front of the actors. (00:45:20)
The Ultimate Computer - S2-E24
Visible crew/equipment: After M-5 fires on the other starships Daystrom speaks to M-5 about the murders, then when Kirk walks over to Daystrom and tells him the M-5 must be destroyed, the shadow of the moving boom mic is visible over Daystrom. The white tape mark is also visible on the floor near Uhura's chair, where McCoy had been standing earlier. (00:42:15)
Visible crew/equipment: After Kirk tells the policeman that he wants to see Merikus and "perhaps" he's a friend, the policemen lock the cell then leave, and when it cuts to a view of the cell from the side as Spock walks over to the steel bars, the overhead boom mic is visible inside the cell, over Spock. It's visible again, with a better view, when McCoy walks over to Spock beside the bars. (00:18:15)
Visible crew/equipment: Set lights are reflected in Spock's tricorder screen before he closes the cover.
Answer: Kirk was getting his physical and Dr. McCoy probably turned off communications, because if he hadn't, Kirk would have left and headed straight for the bridge, leaving McCoy irritated.