Continuity mistake: In the mess tent, when Frank asks Hawkeye why he makes his life so miserable in the OR, notice that in the wideshots there's a silver pitcher, napkin holder, etc. On the table between Trapper and Margaret who are facing each other, but in the shots facing Margaret and Frank, and also Trapper and Hawkeye all of those things vanish and then reappear.
Continuity mistake: When the Swinging Surgeons are performing during the charity no-talent night, Radar's drum kit is set up differently between the wideshots and closeups.
Henry, Please Come Home - S1-E9
Continuity mistake: When Henry's being given the Special Citation of Merit - 4th class, in the wide shot of Hawkeye and Trapper there's dark facial stubble on Hawkeye's face, but in their closeups there's barely any stubble on his face.
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.
Continuity mistake: As Hawkeye writes a letter to his dad, he says "Christmas, here in Korea, as with you in Vermont, is soon upon us." Later, his dad is in Maine, and has lived there all his life.
Continuity mistake: In the Swamp, as Hawkeye asks about Peg's cookies, BJ folds the cards in his hand, and places his left hand over the top. In the close up, as he answers, he suddenly has the cards back in a fan.
Continuity mistake: As Rizzo turns to Potter to give the test score, he puts his cigar in his mouth, and his right hand on his papers. The next shot the cigar is suddenly in his right hand.
Father's Day - S9-E4
Continuity mistake: As Margaret sits on the bunk to talk with Al, his hands are by the table's edge. When the angle changes, they're up at chin level.
Continuity mistake: As Charles talks to the guys in the Swamp, his right hand alternates from up at his chest to down by his side several times too quickly to be normal.
Preventative Medicine - S7-E22
Continuity mistake: In the Mess Tent, as Lacey explains the reason he wants the hill to Margaret, he is holding a knife in his right hand. A second later, it's gone.
Peace on Us - S7-E2
Continuity mistake: As Hawkeye storms out of the Swamp, he leaves Charles, Potter, and BJ behind. After the angle changes, you can see there is nobody in the tent, and the still is missing.
Continuity mistake: When the Jeep runs over the French horn, the crowd is a good distance back. When Potter comes out and picks up the flattened horn, the crowd is only five or six feet away without having moved up.
Continuity mistake: As the discussion about Burns draws to a close, Potter starts to grab the files on his desk. As he says "Dismissed", he grabs them again.
Continuity mistake: From the back, Potter is facing directly at Hawkeye and BJ. From the front, he's in quarter profile, left side forward.
Continuity mistake: As BJ mentions fingernails on a chalkboard, Potter hunches his shoulders up. A second later, after the angle changes, he repeats the action.
Continuity mistake: As Hawkeye talks to the wounded man on the chopper, the speed of the rotor blades changes several times in the scene. Looking at Hawkeye, the blades are moving fast; in the reflection, much slower.
Dear Sigmund - S5-E7
Other mistake: As the ambulance takes off rounding a corner, the back brightens as stage reflectors or lighting rigs shine on it.
Dear Sigmund - S5-E7
Visible crew/equipment: As Potter pans around looking with binoculars, the lighting rig and a crew member can be seen reflected in the lenses.
Visible crew/equipment: As Potter turns away from looking at Burns rousting a man, he walks past the camera talking to himself. As he gets close to the camera, the shadow of the boom mike plays on his left sleeve.
Visible crew/equipment: As Hawkeye and Trapper sit down to talk with McShane, the shadow of the tip of the boom mike can be seen on the door on the right side of the shot. (00:08:25)
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