The Trouble With Tribbles - S2-E15
Continuity mistake: During the scene when the Klingon agent is exposed by the Tribbles, Kirk first holds the two furballs as if they had a handle on the underside (probably for the parts to make them wriggle). As he turns to Spock (the wide-angle shot), he holds the Tribbles cupped in his hands, his thumbs supporting their flanks. But as Kirk approaches Spock (close-up), he has them 'by the handle' again.
The Trouble With Tribbles - S2-E15
Continuity mistake: When Kirk and McCoy dispute about the tribbles on the Enterprise bridge, Kirk holds the two tribbles in his hands at alternate heights. In the shots where McCoy's face is seen, he holds them next under his chins, but when Kirk's face is seen, he holds them at chest level.
The Trouble With Tribbles - S2-E15
Continuity mistake: After Kirk opens the bin, the Tribbles fall on him. At first, he shields his head, then drops his right arm. Suddenly, it's over his head again.
The Trouble With Tribbles - S2-E15
Continuity mistake: During the brawl, as Cyrano Jones watches the action, the glass he quickly raises loses most of the liquid. After he gets half way through the scene, the glass is suddenly almost full.
The Trouble With Tribbles - S2-E15
Continuity mistake: Uhura's image on the conference viewer is of a close up on her face. When the camera looks at the screen, the image is of her head and upper torso. Likewise, when Fitzpatrick is on, first it's his head and torso, then it's only his head and shoulders.
The Gamesters of Triskelion - S2-E16
Revealing mistake: As the camera does a close up of the Master Thrall, the line of the bald skin cap is visible. (00:05:10)
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
Continuity mistake: The Providers' representative colors on the game platform and the thralls' collars (all three colors are on Galt's collar) are red, yellow and blue. But when Kirk appears before them, the Providers themselves are red, yellow and green, and so is the gaming symbol inside their glass bubble. (00:40:00)
The Gamesters of Triskelion - S2-E16
Continuity mistake: During the final match, while Kirk fights the lone Andorian thrall two things to notice. Kirk's collar of obedience opens up and drops between the two opponents, then when Kirk lifts and flips the Andorian thrall the back of Kirk's black pants are split open in the wide shot. Both the collar and pants are intact in following shots. (00:45:25)
The Gamesters of Triskelion - S2-E16
Continuity mistake: At the end, the freed thralls, including Kirk, Chekov and Uhura, remove their collars and throw them onto the game platform. But when Kirk and his crew beam away, the collars have all disappeared. (00:48:40)
The Gamesters of Triskelion - S2-E16
Other mistake: When Kirk agrees to fight in the arena at the end of the episode, he and the thralls are warned that touching an opponent's color will result in the loss of a weapon. Kirk does this several times during the fight, but isn't penalized in any way.
The Gamesters of Triskelion - S2-E16
Other mistake: Kirk tosses the Andorian, and as he hits the ground, his shirt comes up and the man's real skin tone is visible.
The Gamesters of Triskelion - S2-E16
Continuity mistake: When Kirk, Uhura, and Chekov enter the transporter room Kirk is wearing his usual boots with heels, but while they're on Triskelion during some scenes Kirk's boots change to boots with flat rubber soles.
The Gamesters of Triskelion - S2-E16
Revealing mistake: When Kirk goes to kick his opponent, you can see the kick was at least a foot and a half from the man.
The Gamesters of Triskelion - S2-E16
Revealing mistake: When the camera goes in on a close up of the phaser, when the trigger is pulled, the indicator light to signal a reaction by the intended target that's usually too small to be seen or hidden by animation is visible.
The Gamesters of Triskelion - S2-E16
Continuity mistake: As Kirk gets up from the ground on Triskelion, his communicator is open. When he goes to use it, it's closed and he opens it.
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
Continuity mistake: In the very first scene after the intro, when Bela's goons hold the landing party at gunpoint, Spock's position on the sidewalk shifts back and forth from standing on the other side of a wooden bench to standing alongside Kirk and McCoy with no bench in between. In fact, in the latter shots, the bench has moved all the way across the street. (00:04:50)
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)
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.