When hotlips is putting the gown on frank her arms are exposed but after frank is handcuffed the gown n ow completely covers her arms.
When trying to rendezvous with Frank Margaret goes into a tent labeled supply tent. Most other times the supply tent is a metal Quonset hut.
Loretta Swit's fingernails can be seen to be almost an inch long. No nurse, especially a head nurse, would have fingernails that long.
The beer cans that Frank is asked to drink from are modern formed aluminum cans. Beer cans of this era were not made from aluminum, had flat bottoms and had to be opened with a can opener.
Henry states that he can't give AB- blood to the POW in case "one of our kids needs it," so Trapper and Hawkeye look through the personnel records to find a donor with AB- blood. People with AB- blood can receive blood from donors with AB- blood, obviously, but can also receive A-, B-, and O- blood as well. AB- is the rarest blood type, and it would've been easier to find a donor with any compatible blood type.
In the last scene, when Hawkeye & Trapper come in, the North Korean POW says "hi guys" in ENGLISH.
Major Burns scrubs up prior to surgery ( with the help of Major Houlihan), but he never scrubs above the mid forearm. A 7 minute surgical scrub involves the entire forearm. Also, Major Houlihan assists him with his sterile gown, but she is bare handed.