Continuity mistake: The gash on Kirk's right cheek disappears between the time he and McCoy fall asleep in the cave and when McCoy wakes up to find Kirk at Nona's side. (00:21:30 - 00:23:15)
Continuity mistake: When Nona is trying to seduce Kirk, we see a close-up of him with nothing on his shoulders. Cut to a two-shot and suddenly Nona's arms are over his shoulders and around his neck. (00:41:00)
Continuity mistake: In the original version, the planet is the same as the one used in "Bread and Circuses", but when the Enterprise leaves orbit at the end, it is a totally different planet, as it is the one used in "Friday's Child".
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.