The Sniper - S2-E10
Revealing mistake: When The Sniper begins his attack, a sandlot football game is in progress in the compound. As the quarterback goes back to throw a pass, he waits just long enough for the ball to be "shot" out of his hand.
The Sniper - S2-E10
Other mistake: When Hawkeye and Trapper make Frank up to look like MacArthur, as they put the pipe in the "sleeping" Frank's mouth, he opens a bit wider, and bites down on the stem, then says his last line of the episode.
The Sniper - S2-E10
Revealing mistake: When the bottle of liquor is shot, there's no bullet hole in the basket that's right behind it, nor does the basket move from the impact.
The Sniper - S2-E10
Revealing mistake: Toward the end of the episode, Henry is talking to a general on the phone when the chopper is coming in. He's trying to tell the man that he can't hear him. As he continues trying to talk, he gives up, and hangs the receiver up on the skeleton's head. If you look, you can see the hook that was conveniently placed for the gag.
Visible crew/equipment: After Radar walks into the Swamp and gives Hawkeye and Trapper the coffee and case folders, just as Radar tells them that he was too sleepy he walks out, and the actor's chalk T-mark can be seen on the ground (although faint, it's distinguishable).
Factual error: The Logan Ramsey character tells Hawkeye and Trapper that with enough notice he could get them anything, even a B-52. The first B-52A entered service in 1954, a year after the Korean War ended.
Continuity mistake: As the boys talk to Col. Lambert, Trapper is back a bit from the table. When the angle changes, he's a lot closer.
Deal Me Out - S2-E13
Factual error: In this episode, Henry is seen handing Radar the keys to his jeep. While this probably benefited the understanding of the audience, it is historically incorrect. Jeeps assigned to a combat zone were outfitted with an ignition switch, not an ignition lock, for the simple reason that in an emergency the vehicle had to be useable by anyone. (00:03:40)
Deal Me Out - S2-E13
Continuity mistake: During the poker game Frank walks in wearing a white hospital scrub, then the camera pans to Sidney and back to Frank who is now wearing a army jacket. (00:08:12)
Deal Me Out - S2-E13
Continuity mistake: From behind, Klinger's cigar is full length, with no signs of being lit. When he responds to Hawkeye's question, it is noticeably shorter.
Deal Me Out - S2-E13
Visible crew/equipment: After the C.I.D. man comes into the swamp and makes reference to Klinger, who looks up, you can see a studio light panel reflected in his shades.
Hot Lips and Empty Arms - S2-E14
Continuity mistake: When Margaret is seen drunk in Henry's office it is daylight outside. Radar brings news of incoming casualties so they rush outside where it is pitch dark. (00:20:00)
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.
Hot Lips and Empty Arms - S2-E14
Visible crew/equipment: When Margaret walks into Henry's office while Trapper, Henry, and Hawkeye are watching a "training film," the actor's chalk T-mark can be seen on the floor.
Hot Lips and Empty Arms - S2-E14
Other mistake: While trying to sober Margaret up, you can see Trapper's clothing wet in spots where she hung on to him in previous takes.
Hot Lips and Empty Arms - S2-E14
Continuity mistake: In Henry's office, Margaret has pins in her hair over her ears. When she comes out to see Henry, the pins are gone.
Hot Lips and Empty Arms - S2-E14
Continuity mistake: When Margaret comes into Henry's office, interrupting the "training film" Hawkeye's part flips from being on the left to the right and back.
Revealing mistake: The first scene is set in the X-Ray room. There is an X-Ray up on a lightbox in the background. Towards the end of episode 14, there is a scene in the O.R. - the exact same X-Ray is visible in the background there as well. (00:45:00)
Continuity mistake: As the camera looks at the door of the Officer's club while the General and Hawkeye talk, other tents can be seen behind them. As Hawkeye brings in the enlisted personnel, the area is totally empty.
Visible crew/equipment: When Frank and Hot Lips are walking into the mess tent for Frank's surpise party, if you look in the window to the right of the door, you can see a person silhouetted, throwing leaves into the wind.
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