Charles ties a rope from a Jeep to the center tent pole and uses the Jeep to pull the pole down, causing the tent roof to fall. As Charles drives away, you can see the other end of the rope is not tied to anything.
When Hawkeye has Radar send a fake telegram to Charles, the telegram is supposed to say that Charles would once again be under consideration for the position of head of thoracic surgery. When Charles gets the telegram, and he starts speaking again, he tells everyone present that he has gotten the position and will be leaving.
When Dr Freedman places Jerry under hypnosis to recreate how Jerry lost his memory BJ calls out Corpsman. The US Army uses the term Medic. The USMC uses the term Corpsman.