Trapper relates that the unit treated 473 casualties in 36 hours. With only a 10-12 bed post- operative ward, this is highly improbable.
The doctors are supposed to be driving into Chinese territory. To do so they would have to drive straight through North Korea--for at least 300 miles. This is not likely.
While singing, guitarist Spalding repeatedly pronounces "sashimi" as "shashimi".
The rendezvous point, Rainbow Bridge, is said to be fifty miles behind enemy lines. The chances of the doctors and crew even making it to Rainbow Bridge without being killed or captured would be practically nil, because they would be sure to encounter enemy forces that had no knowledge of them being "invited" by the Chinese unit with the wounded POWs.
LTC Blake would have been court-martialed for sending personnel -- especially non-combat personnel -- on a mission behind enemy lines. Permission from I Corps unquestionably would have been required.
Although Loudon Wainwright III's character, Calvin Spalding, holds the rank of Captain, he is shown with First Lieutenant bars on the shoulder of his shirt.
When Frank handles Margaret's gun, his finger immediately goes to the trigger ( as it does every time he takes a gun in hand). Even doctors would have had basic firearms training, and that is considered a major safety violation. He also has the gun pointed directly at Margaret's head.
Dr. Tam, the Chinese doctor, tells the M*A*S*H doctors to drive across the bridge, then they end up simply carrying them without ever moving the bus again.