Continuity mistake: When Hawkeye gets into the chow line and Igor suggests the peas and carrots, Hawkeye asks about the beans. As the peas and carrots are being scooped to be served to Hawkeye, he grabs Igor's arm and peas and carrots are spilled into the beans. Peas are VERY visible in the beans. The next shot with the beans, the peas and carrots have been removed from the beans.
Continuity mistake: After Klinger's file cabinet gets bombed, BJ appears in the window. He's facing directly ahead, head slightly tilted to the right. When the camera goes to a close up, he's in quarter profile, left cheek forward. In the long shot, he's back to the original position.
Continuity mistake: When BJ is letting Hawkeye in on the fact the he was the only real victim of the gag, he's putting a forkful of eggs in his mouth. After the camera cuts to Margaret and back, he doing it again. His mouth was empty both times.
Continuity mistake: After the files blow up, Klinger sees BJ looking at them. If you look carefully, you see that his head changes position between shots.
Continuity mistake: When filming Hawkeye, BJ and Charles in the swamp before they go to Potter's tent, the camera has a clear, unobstructed view of the inside. When it pulls back you can see the end of the tent, but without the netting normally there.
Continuity mistake: When BJ comes out of the building and meets Paul, you can see a chain-link fence in the background that you never see any other time in the series.
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