Visible crew/equipment: As Hawkeye and Trapper sit down to talk with McShane, the shadow of the tip of the boom mic can be seen on the door on the right side of the shot. (00:08:25)
Visible crew/equipment: When Trapper and Hawkeye walk into the Swamp and find Dr. Pak waiting for them, the edge of the tent set can be seen at the top left corner of the screen.
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