The Return of the Archons - S1-E22
Visible crew/equipment: After Scotty tells Kirk that the shields are unable to deflect the heat beams, the piercing soundwaves knock everyone out, and when Kirk awakens in the cell he tries to wake Spock, then the shadow of the camera is visible on the pillar as it follows Kirk. (00:25:55)
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.