They Call the Wind Korea - S7-E7
Continuity mistake: When Klinger is coming over the hill at the end of the episode, the camera shows him in the outdoor setting, and the spot he's on has sparse vegetation. When the camera goes to a close up of him, the trees and shrubs are thicker and closer to him. This alternates a couple of times.
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