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.
L.I.P. (Local Indigenous Personnel) - S2-E7
Continuity mistake: The C.I.D man's hat goes from straight to crooked between cuts in the swamp as he tries to leave.
Continuity mistake: Frank comes over to talk to Hawkeye and Trapper. His arms go from down by his sides to hands on hips between angles.
Continuity mistake: The crew is getting the bad news in Henry's office when Radar reports more choppers. From behind, Henry starts to react, and when the angle changes he reacts again.
Continuity mistake: When Henry is shaving, he hears a knock at the door. After he says "Come in", the door opens and a cow comes in. Trouble is, the door normally opens outwards, but for the gag to work, this time it opens inwards.
As You Were - S2-E20
Continuity mistake: Hawkeye pulls the blanket over Frank's right arm, then pulls his left arm up to take his pulse. In the following closeup Frank's right arm is uncovered, and the blanket is below the screen. (00:18:45)
Continuity mistake: When Blake is talking to Burns, he sits and plays with his doll, which is facing toward the office door. After the angle change, the doll is facing Henry.
Continuity mistake: When the General comes up, Pierce and Trapper are walking away toward the camera's left. When Pierce calls for the General's attention he is shown gesturing to the open door. Problem is, that they should be looking over their left, not right, shoulders, and we should see the inside, not outside, of the door.
Continuity mistake: While talking to Hildebrandt, Henry smacks his hands together while saying "Gee, whiz!" When the angle changes, his hands are on the desk.
Continuity mistake: Usually when you see Pierce, his hair is parted on the left side. When he is nibbling on the nurse's neck in the Swamp, his hair is parted on the right. Then the next time he's seen, it's parted on the left again.
Continuity mistake: When Margret puts The Gun belt around Frank's waist, it is twisted in the back. After the cut, it is righted. (00:02:30)
Continuity mistake: When Hawkeye passes by Frank on his way to Lt. Johnson's, he's holding a bottle of gin up near his waist. In the next shot, his arm is resting down by his side. (00:08:30)
Continuity mistake: When Hot Lips calls General Clayton to her tent, he closes the door twice. (00:11:45)
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