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)
Revealing mistake: During the fight between Kirk and Tracey, the outline of the knee pads under Kirk's pants are visible, particularly while Kirk is on the floor with his knees bent.
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)
Continuity mistake: When Kirk and McCoy join Spock and Galloway on Exeter's bridge, McCoy kneels down and uses his med tricorder with its strap crossed over his shoulder, but in McCoy's closeup the strap is gone, then next shot the strap is once again over McCoy's shoulder. (00:04:25)
Deliberate mistake: When Spock is brought to the Yang ceremony to join Kirk and McCoy, after Spock responds that although he is weak their "need for departure is even more immediate," the very next closeup of Kirk is a flipped shot. (00:34:15)
Continuity mistake: When Kirk confronts Spock in his quarters, Kirk asks if it's something only his planet can do for him, then Kirk uses his left hand to grab hold of Spock's arm as he drops the stylus, but in the closeup it's Kirk's right hand holding Spock's arm up, and that stylus is also back in Spock's raised hand. (00:12:25)
Visible crew/equipment: After Kirk and Spock place Hengist on the transporter platform to beam out, when McCoy and Scotty join them two white tape marks are visible on the floor. McCoy stands at one tape mark before Kirk begins to describe beaming it out into open space, and Scotty stands at the other tape mark as Kirk realises he'll be going alone to the cafe.
Visible crew/equipment: During Scotty's testimony, when Hengist agrees to the psycho-tricorder analysis of Scotty's memory Kirk tells Scotty he can step down, and the white tape mark is visible on the floor where Kirk stands. (00:28:20)
Deliberate mistake: After one of the enemy villagers stabs Nona, during the ensuing fight when Kirk does a flying dropkick on a villager, this semi-closeup and the next wide shot are both flipped shots - the leather band is on Kirk's left upper arm, instead of his right. (00:46:15)
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
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
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)
Continuity mistake: After Maab gives Eleen back her life and forfeits his own life, when Keel throws the kleegat and hits Kras he drops the phaser in the closeup, but in the next long shot the phaser is back up in the Klingon's (stuntman) right hand. (00:45:50)
Visible crew/equipment: When Kirk regains consciousness in sickbay he asks McCoy about Sarek, and as the camera turns we see the white tape mark on the floor in front of Amanda's feet. (00:35:20)
Visible crew/equipment: While Spock and McCoy are discussing the dangers of the experimental drug, when McCoy tells Spock that he can't sanction it, the two white tape marks are visible on the floor. (00:26:30)
Visible crew/equipment: While Sarek is lying in sickbay, McCoy, Spock, and Kirk discuss the open heart procedure, and when Christine walks over to stand beside Sarek, the white tape mark is visible on the floor where she stands. (00:24:20)
Visible crew/equipment: When Kirk walks into the brig Spock tells him that Nomad has almost human stubbornness, and that its screens are still up, then just as Kirk moves closer to Nomad the shadow of the moving boom mic is visible at the top, left side of the screen. (00:28:15)
The Trouble With Tribbles - S2-E15
Visible crew/equipment: After Mr. Baris takes Darvin into custody and leaves the room, when Kirk walks over to Captain Koloth three white tape marks are visible on the floor. (00:45:10)
A Piece of the Action - S2-E17
Continuity mistake: When Kirk is talking to Oxmyx across the pool table, the yellow 1 ball is shown close to Kirk, then Oxmyx, and back.
Visible crew/equipment: A stagehand's foot is visible before the party beams down. (00:09:10)
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.