Audio problem: At the end of the show, when Trapper is playing his instrument, the music does not match the movements of his hand.
Continuity mistake: In some shots the Spam lamb has mashed potato eyes and a carrot mouth, in others it has green grape eyes and no obvious mouth, and it keeps changing. (00:23:10)
Visible crew/equipment: While the Greek shipment of food is being brought into the mess tent, when the cook carrying the lamb walks behind the table, the edge of the tent set can be seen at the top right corner of the screen.
Continuity mistake: In the shot where Hawkeye presents the Spam lamb to Henry, he sets it down, and Henry asks him what it is. Behind Henry, you can see Hawkeye's shadow - and see his lips mouth the word "A Spam lamb". The camera then changes to a close-up of Hawkeye, saying "A Spam lamb".
Visible crew/equipment: While Trapper and Hawkeye are already in Henry's office Radar and Henry walk in, and just as Henry says, "Everything in this country disappears except me," the shadow of the boom mic can be seen moving across the wall at the top right side of the screen.
Continuity mistake: When Radar goes to get the lamb, he pulls out a hypo to put the lamb to sleep for shipping. When the shot cuts to the lamb, you can see both of Radar's hands on the lamb's face; no hypo in sight.
Revealing mistake: The sound of crew making an explosion with their mouth as a cue can be heard just before the actual audio of an explosion plays.
Answer: Even an Army field hospital would have SOME weapons for self-defense if the enemy attacked. What's meant is that it's not a combat outfit, and therefore wouldn't have enough weapons to actually attack anyone. (It's also mentioned a few times that the Officer of the Watch is supposed to carry a pistol at all times, but Hawkeye refuses to do it when he's in charge and Colonels Blake and Potter don't enforce the rule).
Captain Defenestrator