Continuity mistake: In the turbolift, Chekov is standing to the left, but when the door opens he has moved to the right and exits behind Spock. (00:10:40)
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.
Space Seed - S1-E23
Other mistake: Spock calls for McGivers and Scotty to the transporter room. In the Transporter Room, Scotty is at the controls, then after he went to the Transporter pad, they used a stock shot of his hands working the controls.
Revealing mistake: When first seen on Gothos, the "frozen" Kirk's eyes blink.
Space Seed - S1-E23
Revealing mistake: During the fight sequence between Kirk and Khan in the engine room, you can see in some shots that it is not William Shatner and Ricardo Montalban fighting, but their stunt doubles.
Space Seed - S1-E23
Visible crew/equipment: When Khan hides behind the wall in the engine room before Kirk enters, a crew member walks in front of the stage light and you can see the shadow of his head passing across the floor.
Shore Leave - S1-E16
Revealing mistake: When Yeoman Barrow places her tunic on a shrub while changing, automobiles can be seen in the background through the brush.
Continuity mistake: Latimer falls down face down but when picked up he is already face up.
Continuity mistake: Gary Seven pushes a pen holder over to open the doors. The pen wasn't returned to the upright position, but was up when Kirk came in.
Shore Leave - S1-E16
Continuity mistake: At the end Angela is not with the group then strangely reappears without any reason given.
Continuity mistake: After Spock and Kirk attempt to trap Charlie into a room with a force field, Charlie makes the wall disappear and then freezes Kirk and Spock in place. Spock has his right hand against the wall at about chest level with himself. The camera cuts to a closer angle and suddenly his hand is higher up, about face level. (00:39:47)
Continuity mistake: When Kirk begins to question Charlie about the melted chess pieces, there is a close up of Kirk showing light cast down him him with his chest void of any shadows. When cut to a wide angle, he suddenly has shadows on his chest from lighting changes. (00:22:36)
Continuity mistake: Uhura starts to sing and walk around Spock as he plays. In Spock's close ups, the wall behind him is pink and green, but in the further shots the walls are a blue color with nothing behind him that could have been making the green and pink colors in the close ups. (00:10:50)
Audio problem: When Uhura apologizes to Spock for interrupting him playing his instrument, her word is cut off mid speak between cuts. She says "I'm sorr-." But it's close enough it easily got past the editor or the editor cut her word off too soon not realizing. (00:09:59)
Continuity mistake: Just before Uhura begins to hum with Spock's playing of his instrument, she is leaning over a table where they are playing cards. She has one hand on her cheek and then brings the other up to her face as well. When it cuts to a side angle, she's suddenly bringing her hand up to her face again in a repeated action. (00:09:47)
Continuity mistake: After Bones finishes examining Charlie, they move to the door and Charlie begins to put his jacket back on. In the side shot, he gets it on and begins to adjust it around his shoulders when it cuts to a frontal view. Suddenly his arms are relaxed like he's already had the jacket on for a few seconds and in a comfortable position. (00:05:18)
The Man Trap - S1-E2
Continuity mistake: When the creature makes it's way through the ship and finds McCoy's room, it stops near the wall with a red vent behind it. It changes back to Nancy in a dissolve cut, but suddenly it's much closer to the walk and is now closer to the vent, something that would not have happened by a simple morph like seen before. (00:28:45)
The Man Trap - S1-E2
Continuity mistake: When Kirk is telling Crater that he needs him and his wife to stay on their ship till he finds out what killed his man, Kirk has his arms crossed. When Crater steps up to him and the angle changes, Kirk's arms are suddenly down at his side. This continuously changes back and forth between shots. (00:18:07)
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.