Visible crew/equipment: In the compound, as the camera pans to follow Potter coming toward Hawkeye, the corner of the studio is easily seen through the camo net, above the building.
Continuity mistake: In the Operating Room, as Charles hears that his phonograph has been "donated" for use during the emergency, he turns his head from left to right. In the close up, he lifts his head.
Continuity mistake: When the bomb disposal sergeant is sitting down at the end of the episode, he's facing the table. When the camera cuts in closer, his left shoulder is facing the table.
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