Continuity mistake: As the team of 4 energize from Enterprise to go to Exeter, the positions of Spock and Lt. Gallway are altered as they re-emerge on the other side.
Continuity mistake: As Kirk wipes a tear from Elaan's face, both cheeks are wet. A second later, both cheeks are dry.
Continuity mistake: In sick bay, close ups of Sarek show him sitting up at a 90 degree angle, but the long shots show him reclining at a 45 degree angle as the shots cut away and back.
Factual error: Throughout the episode, there is a constant reference to 5 p.m. being the time Kirk and crew (a.k.a., the Clanton gang) were to die. However, the real 30-second shootout was at 3 p.m.
The Ultimate Computer - S2-E24
Audio problem: After trying to change course, Sulu calls Kirk. Kirk says "Kirk here", and then you hear the click of the comm button being hit.
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
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.
Continuity mistake: As Scotty starts prying the panel open, it's with a tool in his right hand, and the thumb of his left. After the cut, he's suddenly holding it in his right hand.
Other mistake: After Scotty makes his remarks to Spock, he raises his phaser. The sparks start up before Scotty levels his phaser.
Revealing mistake: As Spock gets to to the helm position, the whole console visibly wobbles as he hits the controls.
Continuity mistake: As Christine goes to put the respirator in place, she uses her right hand. After the cut, it's her left that puts it in place.
Continuity mistake: As Bones works on Joe's injury, a red light turns on over his head shining down on the area, illuminating his hair. A second later, the red is gone, then back.
Continuity mistake: The indicators radically change positions when Spock gets on the bio bed.
Continuity mistake: When Sulu confronts the men in the corridor, his epee goes from perfectly straight to having a slight crook, then back to straight when he appears on the bridge.
Continuity mistake: As Joe draws back and stands up, he pulls a knife. First, it's sharp side up, then it's suddenly blade down.
Continuity mistake: The background of the cell does not jibe with the positions of Kirk and Cloud William as they fight - where Kirk and Cloud William should have either the cell's bars or the exposed brick wall behind them, there are shots of the opposite wall behind them instead, which is a plastered rock facing.
Visible crew/equipment: The shadow of a boom mic is seen against the rock walls of the cave follows Spock and McCoy when Spock pulls McCoy off Zarabeth.
Revealing mistake: When Mr Hengist goes on the rampage in the hearing room, you can see that the actor playing Hengist is an obvious stunt double wearing a bald cap, whereas John Fiedler has hair on the back and sides.
Requiem for Methuselah - S3-E19
Continuity mistake: When looking at the view screen from the helm, there is a man sitting at the Conn position, but in the wide angle, there's a woman there.
Requiem for Methuselah - S3-E19
Other mistake: If the ship had not been in visual communication, there's no way Kirk could have seen the Bridge or the crew in suspension.
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.