Where No Man Has Gone Before - S1-E4
Visible crew/equipment: When Mitchell tells Kelso that Dehner is a "walking freezer unit" we can see wires and other equipment on the floor, in front of the helm and navigation console. (00:05:35)
Where No Man Has Gone Before - S1-E4
Revealing mistake: After the ship enters the galactic barrier, when Kirk orders "navigation on automatic" there are flashes of light, and in a closeup of the first console just to the left of the main viewscreen, we can see the special effects material spread across the panel below the controls, for the fire to burn when it explodes. Then it cuts to the wideshot as a second console (near Spock's station) blows up, but in the background that first console is intact - no fire/damage whatsoever (it explodes again in a following wideshot). (00:10:00)
Where No Man Has Gone Before - S1-E4
Visible crew/equipment: When Dr. Dehner is talking to Gary Mitchell in sick bay, when he grabs her arm you can see the shadow of the boom mic on the door and adjacent wall. (00:19:25)
Where No Man Has Gone Before - S1-E4
Character mistake: When Sulu is explaining the mathematics of Gary Mitchell's powers getting stronger, he says they are increasing "Geometrically", and then uses the popular example of doubling a penny every day for a month. What Sulu is describing would actually be exponentially. (00:24:14)
Where No Man Has Gone Before - S1-E4
Visible crew/equipment: After Kirk's briefing regarding Mitchell's abilities, when Spock and Kirk are alone just as Spock says that they'll never reach an earth base with Mitchell aboard, the boom mic casts a shadow overhead until Spock steps forward, and a bit can be seen again when Spock tells Kirk that it's his only choice. (00:24:50)
Where No Man Has Gone Before - S1-E4
Visible crew/equipment: While Kirk, Spock, and Dr. Dehner are with Gary in sickbay, when Gary makes threatening remarks and gets out of his bed, the shadow of the moving boom mic is visible on the wall at the left side of the screen. (00:28:55)
Where No Man Has Gone Before - S1-E4
Visible crew/equipment: While Kirk is armed with a phaser rifle he quietly moves closer to Gary and Dr. Dehner, but when Gary senses the "foolish man" he causes a boulder to roll past Kirk, and the arm of a crew member is visible behind the boulder pushing it forward. (00:39:40)
Where No Man Has Gone Before - S1-E4
Continuity mistake: When Kirk is fighting Gary Mitchell, his tombstone reads James R. Kirk. Kirk's middle name is Tiberius. Mitchell is a friend of long standing and would not have got it wrong. (00:44:30)
Where No Man Has Gone Before - S1-E4
Revealing mistake: When Kirk & Spock are watching Gary read the pages on the monitor one after the other, look closely: it's the same two pages back and forth.
Where No Man Has Gone Before - S1-E4
Revealing mistake: The readers in Sick Bay are supposed to be display screens, a type of CRT, for reading material. Mitchell turns his off to rest, but the words are still plainly visible.
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.
Continuity mistake: Initially, the Enterprise orbits Psi 2000 as the planet turns westward. But in later shots, on the bridge view screen, the planet has reversed directions and now turns eastward. (00:04:05 - 00:12:00)
Revealing mistake: As the bridge crew monitors Psi 2000 on the view screen, a glitch in the special effects matte makes the planet vanish briefly and then reappear - twice. (00:12:30)
Visible crew/equipment: When Spock walks into the briefing room, he stands in front of the closed doors telling himself that he's in control of his emotions, and when he says, "My duty," the shadow of the boom mic can be seen moving across the wall at the top of the screen. (00:36:40)
Character mistake: Lt. Joey said to Lt. Sulu "You don't outrank me and you don't have pointed ears" but Joey is a junior grade lieutenant so Sulu would outrank him.
Visible crew/equipment: As Spock swings the scanner around, as it points toward the camera position, the camera equipment is reflected on the chrome plate on the front.
Other mistake: In the Briefing Room, while Kirk is feeling the effects of the disease, Spock tells Scotty that he will call the restart formula in from the bridge. But just a moment later, Kirk enters the Bridge, and Spock is in the Engine Room working on the settings and formula with Scotty.
Continuity mistake: In the opening, the crewman gets a few drops of the infectant on his hand, but the reddish mass on the wall remains. On the ship, when the spectral view is shown, the red mass is nowhere to be seen.
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.
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.