The General's Practitioner - S5-E20
Continuity mistake: Near the beginning, while Col. Bidwell is watching Hawkeye operate, in the closeups he is standing by the window but in the wide shots he is standing in a different part of the O.R. (00:04:00)
The General's Practitioner - S5-E20
Visible crew/equipment: When the Colonel that Hawkeye referred to as "Bozo" is talking to General Korso on the way to the 4077th to get Hawkeye, you can see the shadow of the camera on the Colonel's lap.
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