Space Seed - S1-E23
Continuity mistake: At the hearing in the final scene, there are two bits of debris of some sort (small, black and roundish) littering the floor at the bottom left of the screen. Whatever it was disappears when Scott, Spock, Kirk and McCoy get up to leave the room. (00:48:20)
Space Seed - S1-E23
Continuity mistake: When the landing party beams over at the beginning, the transporting officer is wearing a blue jumpsuit, but when they go to the closeup of his hands, they have a red uniform, two braid stripes, and are the standard shot they use when Scotty does the transporting. (00:05:05)
Space Seed - S1-E23
Continuity mistake: As the away team observes Khan in the stasis chamber, McCoy holds his tricorder with both hands, but the next shot shows him holding it in one hand.
Space Seed - S1-E23
Continuity mistake: On the Botany Bay, McCoy is not holding his tricorder, but when the ship's lights activate, McCoy suddenly has his tricorder in his hands.
Space Seed - S1-E23
Continuity mistake: When Khan asks Kirk "How long?" Kirk's head is near Khan's with nobody behind his head, but the next long shot shows Scotty behind Khan.
Space Seed - S1-E23
Continuity mistake: Khan's hands switch positions several times on the table between quick cuts as he and Kirk talk.
Space Seed - S1-E23
Continuity mistake: At the compression chamber, the pressure meter goes from thirty to ten too quickly to be accurate between shots. After showing ten, the meter jumps back to twenty.
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.