Continuity mistake: The shots of the rocket Scotty cycles through are of different times. There is one shot of the rocket at the launch site, followed by one of the transport taking the rocket to the site.
Continuity mistake: As Kirk talks to Chekov on the screen, his hands are flat on the table, and there is a collection of data tapes in front of him. After the angle change, his hands are clasped on the table, the tapes have been replaced by a data pad, and Kirk appears to be frozen.
Tomorrow is Yesterday - S1-E20
Continuity mistake: When the plane is coming up to intercept the Enterprise, it's shown flying through thin clouds, yet when inside the cockpit, there are no clouds to be seen.
Continuity mistake: At the end, Lt. Moreau gives Kirk a report to sign. After signing and giving it back, and after a dialog with Spock, he gets up, goes to Moreau, has the report and looks at it again.
Continuity mistake: First, Scotty rigged a self destruct delay timer for Kirk that supposedly had thirty seconds programmed in. However, putting a timer against the one used in the episode, from start to finish there was one minute twenty seconds before the Constellation blew up. Second, Kirk was holding the communicator out and away from himself before his beaming, then it's close to his face as he materializes. (00:47:05)
Continuity mistake: Decker is leaning over the forward console between Sulu and the other man, with Spock at his left elbow. As he gives the order to veer off, he starts to turn to his right. As the angle changes, it appears that he was standing straight up the whole time.
This Side of Paradise - S1-E25
Continuity mistake: As Spock and Kirk are fighting, Spock pushes Kirk to the wall after bending the bar with his first blow. The bent bar falls to the ground and ends up against the wall by Kirk’s feet. Moments later, the bar is nowhere to be found.
The Return of the Archons - S1-E22
Continuity mistake: While Kirk is attempting to convince Marplon and Reger to take them to Landru, a distant shot shows Marplon's right hand descend from his chest to his side. Immediately thereafter, a close-up shows Marplon's hand again suddenly at his chest.
Continuity mistake: During Kirk and Lt. Shaw's conversation where Kirk learns that Shaw will be the prosecuting attorney, they are sitting at a table. A shot from behind Shaw's left shoulder shows her turning her head toward Kirk. The scene then shifts to a close-up front shot of Shaw, where she again turns her head.
Continuity mistake: When Kirk intervenes to keep Losira from touching Sulu, she jumps back about two feet and stops. When the camera cuts to look at her, she's still moving, and is about ten feet from Kirk.
Continuity mistake: When Kirk, Bones, Chekov, and Spock go over to the Defiant, the suits they have on have a black support bar in the left side of the headpiece. When the camera looks down at the dead men and back to Kirk, you see the bar is on the right, and his hair is parted on the right. The very next look at Kirk, the bar and the part of his hair is back on the left.
Continuity mistake: After Sam tosses Kirk, he goes to a bench in the corner, picks up the towel that was there, and sits down. After Kirk tosses Charlie, Sam is laughing, and Charlie makes Sam "go away." After Sam fades out, the towel that he had around his neck is lying there, when it disappeared with Sam. (00:27:36)
The Immunity Syndrome - S2-E18
Continuity mistake: During the teaser, Lt. Kyle is wearing a red tunic, but when Spock returns to the bridge after his examination, Kyle is now wearing a gold tunic.
Continuity mistake: Midway through the episode, a stock shot of the view screen shows Sulu at the helm. When we return to the bridge master shot, however, Sulu isn't there. Styles is the only one at the console, and he's sitting at navigation. The helmsman's chair is empty. (00:32:05)
Continuity mistake: When Scotty awakens in the sick room after being attacked by Nomad, Nurse Chapel has her hands placed on him. In the next shot, when McCoy tells Scotty to take it easy, Nurse Chapel's hands are no longer on Scotty, and in the next shot, her hands are back on him.
Continuity mistake: When the security team is escorting Nomad back to the holding area, he goes his own way. One of the team then says, "Hey Nomad!" and begins to reach for his phaser. But in the next shot, he has already got his phaser out and trained on Nomad.
Continuity mistake: The Klingon is standing on a hillside above Maab, yet when he fires his phaser, the beam streaks upward. From that angle, he wouldn't have hit anything but sky. Nevertheless, the beam somehow re-angles itself downward so that it hits and kills Maab. (00:46:05)
Continuity mistake: Mr Checkov has a rather unfortunate hair styling during the beginning of his role in Season 2. In this episode his hair is normal until the end, where in between being given an order and carrying it out he somehow manages to go and have his hair professionally done and made all bouffant. (00:47:15)
Continuity mistake: Mr. Sulu's equipment comes up to aid him at red alert, yet shortly after it is gone. (00:39:00 - 00:40:00)
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.