Continuity mistake: In the episode "It Happened One Night", Klinger has B Positive blood type. In the episode "C*A*V*E*", Klinger has AB Negative blood type. Blood types *never* change.
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)
Continuity mistake: In the episode 'Chief Surgeon Who' (season one), near the end of the episode we see Radar in Col. Blake's office smoking a cigar with ease, but in the first episode of season six when Col. Potter offers Radar a cigar, he doesn't know how to smoke it and he throws up after he puffs it.
Continuity mistake: When Hawkeye is examining the orphan who is wiggling his tongue, there are two camera angles: one of Hawkeye from the front and one of the orphan over Hawkeye's shoulder. In the first shot, the tongue depresser that Hawkeye is holding is horizontal, in the other it is vertical. This flips back and forth a couple of times. (00:06:30)
Continuity mistake: When Radar is going to bed, he takes his shirt off and his upper body is naked. When he puts the blanket over his teddy bear you can see sleeves. Next shot, he is naked again.
Continuity mistake: Margaret is shampooing Frank's hair; she raises her foam covered hands to allow him to kiss her. The camera angle changes and her hands are nearly foam-free. (00:03:25)
Continuity mistake: In the episode Iron Guts Kelly, Col. Wardman first calls Iron Gut Kelly a Lt. General, then a Maj. General then he goes back to Lt. General.
Hot Lips and Empty Arms - S2-E14
Continuity mistake: Margaret is in Henry's office drunk and she tells Henry that he looks just like her father did before he died. In Season 9. Episode 4 "Father's Day" Margaret's father, Alvin 'Howitzer' Houlihan, visits her at the 4077.
Continuity mistake: When BJ and Hawkeye are trying to find out who snitched on Potter, they search Charles' belongings back at The Swamp. BJ wraps Charles' white scarf around his neck. Once Charles returns to his tent, the scarf changes positions several times.
For the Good of the Outfit - S2-E4
Continuity mistake: Henry pops out the golf ball he is washing into the towel. After he finishes talking to Hawkeye, he resumes washing. However, no ball is missing from the dirty pile. (00:02:45)
Sometimes You Hear the Bullet - S1-E17
Continuity mistake: Hawkeye lifts Wendell's arm, takes his pulse and lays his arm down by his side again. In the next shot, Wendell's arm is across his chest. (00:13:55)
Continuity mistake: When Margaret pins on Frank's purple heart, his scrubs are very damp with sweat. When he enters the swamp, they're practically dry. (00:03:50)
Sometimes You Hear the Bullet - S1-E17
Continuity mistake: As Frank receives his purple heart, Henry calls him 'Franklin D. Burns' All other references to his full name in the series give his middle name as 'Marion'. (00:23:50)
Continuity mistake: Charles (in scrubs), Radar, and Father Mulchahy are all in the changing room when Radar and Mulchahy go take a phone call. When entering the comm room, Charles has appeared and is complaining about waiting for a phone call in his fatigues.
Continuity mistake: After Hawkeye and Burns drive through the puddle, the mud on the colonel's face is different in the long and closeup shots. (00:02:00)
Continuity mistake: When Margaret arrives from Tokyo, BJ and Hawkeye's squashed orange disappears from the ground. (00:05:35)
Continuity mistake: During the scene which culminates in Frank declaring the camp dry the patches of water on his helmet change position. (00:05:50)
Continuity mistake: When Frank is getting drunk he spills gin down the front of his vest. A few shots later, just before he collapses, it suddenly dries out significantly. (00:13:20)
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