Visible crew/equipment: After Garrovick is relieved of his duties, Kirk tells McCoy and Spock to make comments and recommendations in their reports, then Garrovick returns to his quarters. Just as Kirk exits the turbo lift on the bridge, the boom mic is visible at the top, left side of the screen. Then when Kirk apologizes to Scotty, in the next wide shot two pieces of filming equipment are visible at the top of the screen. (00:17:20)
Continuity mistake: Dr. McCoy's medical tunic has an engineering patch on it, instead of the science patch it should have.
Continuity mistake: At the end, when Kirk and Garrovick are beamed up seconds before the explosion, Kirk is holding his communicator up to his mouth with both hands. But when they finally materialize on the Enterprise, Kirk's hands are down at his sides: no communicator in sight. (00:47:00 - 00:48:10)
Continuity mistake: On the planet surface, in the scene where the three security men walk around the rock, Garrovick has his arm up with his phaser. When the camera angle cuts to him alone, his arm is suddenly down.
Revealing mistake: When Kirk and Garrovick are fighting at the end, Kirk knocks him down. As he helps him up, Garrovick leans against a huge boulder and the papier-mache rock moves very noticeably.
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.