There were other surgeons at the 4077th
There were other surgeons and doctors at 4077th besides the main characters, Spearchucker, Capt. Spaulding.
In "Sometimes you here the Bullet" there are two other doctors working on patients when Hawkeye and Trapper walk into the OR and first examine Ron Howard.
In "Officer's Only" Hawkeye and Trapper are working on General Mitchell's son. Henry is talking to them wearing his fishing outfit. Frank walks in with Hot Lips scrubbed for surgery yet there is a doctor clearly seen working on a patient. A white doctor at that and its after Spearchucker left so who is the other Doctor? Later on in the final scene at the officer's club there are several male officers wearing medical corps insignia drinking and dancing.