The Immunity Syndrome - S2-E18
Continuity mistake: When McCoy escorts Spock to the shuttlecraft hangar McCoy is wearing his short-sleeved medical tunic, but when Spock suggests that the doctor could wish him luck, in the next closeup McCoy is wearing his long-sleeved uniform. (00:29:40)
The Immunity Syndrome - S2-E18
Continuity mistake: At the shuttle craft deck, Spock is standing on the same side of the door as McCoy, then moves to the other side. When McCoy looks at Spock, he is standing on McCoy's side of the door again, then is back on the other side when the door opens.
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.
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.