A Taste of Armageddon - S1-E24
Continuity mistake: At the door, as Spock gives Yeoman Tamura her orders, his hands are in front of him. In the close up, they are suddenly by his sides.
Continuity mistake: The hilt of the blade Kirk holds against Tracy's throat is close to Tracy's jawbone in the close ups and further away in the long shots.
And the Children Shall Lead - S3-E4
Continuity mistake: When Gorgon the Angel is on the bridge with the children, the positions of the children are different depending if the shot is from the rear of the children or the front.
The Enterprise Incident - S3-E2
Continuity mistake: When the guard opens the cell barrier, the light bars turn off, then slide back. As they come back out, they're already on, rather than the reverse of the opening procedure.
Continuity mistake: To open the secret doors, Seven tilts one of the pen holders down to the top of the desk. After he's gone, Ms. Lincoln comes in looking for him, and the pen is upright without it having been pulled back up, unless it was supposed to reset itself.
A Piece of the Action - S2-E17
Continuity mistake: The pistol Kirk is pointing at the gangster changes elevation and angle as the scene cuts between the front of Kirk and over his shoulder.
A Piece of the Action - S2-E17
Continuity mistake: The scene outside shows a guard standing close to a sign on the wall that says, "Jo Jo Krako", but the next overhead shot shows the guard further away, and a railing between the sign and the guard that would have prevented anyone from getting close to it.
A Piece of the Action - S2-E17
Continuity mistake: When Krako's men are in the gun battle with Bela's men, the Enterprise stuns them with its phasers. The number of bodies and their positions change after the men are stunned.
Continuity mistake: In the reception room, Amanda's glass goes from 1/4 filled after McCoy poured more, to over 3/4 full without his adding more.
Continuity mistake: After landing on the planet, the interior walls of the shuttle craft or well-lit, and light green in color. As Kirk and party exit, the interior is seen to be dark and gray.
Continuity mistake: In Norman's chamber, the medallions on Alice 3 and 11 go from blinking to steady, to totally off and back to blinking through the scene.
The Return of the Archons - S1-E22
Continuity mistake: As Marpon talks to Spock, his right hand goes from being palm forward toward Spock, to being vertical, palm open, thumb upwards, and back.
The Return of the Archons - S1-E22
Continuity mistake: As Kirk talks to an "absorbed" McCoy, in the back-and-forth cuts between them, the part in Kirk's hair jumps from left to right and back.
The Return of the Archons - S1-E22
Continuity mistake: After the Law Giver kills Tamar, he starts to raise his staff. When the camera is in a close up on the Law Giver a second later, it's straight out again. (00:13:15)
Continuity mistake: After swiping at Trelane to score a hit, which Trelane avoids easily, Kirk throws the sword away, which hits a bush as it falls. When Trelane calls up another sword, the bush suddenly stops moving.
The Corbomite Maneuver - S1-E11
Continuity mistake: While beaming to the alien ship, McCoy has his hands on his knees. When materializing, they are beside his thighs.
Mudd's Women - S1-E7
Continuity mistake: In the briefing room, after Mudd is forced to give his real name, the screen lights up with his record of offenses. In the picture, his image has the ear bauble on the right ear, but he wears it on the left.
Where No Man Has Gone Before - S1-E4
Continuity mistake: As Kirk, Spock and Mitchell exit the lift, Yeoman Smith is by the door and begins to follow, and an un-named guy walks by her and into the lift. In the wide shot of the bridge, the actions of Smith and the crewman are repeated.
Where No Man Has Gone Before - S1-E4
Continuity mistake: After Mitchell relieves him, Mr. Alden walks past Yeoman Smith. As he does, he suddenly disappears as Kirk is sitting in his chair. (00:03:55)
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.