Other mistake: During the game, when the second bomb goes off, the whole building is shaking and things are falling all around but the drinks on the table do not move at all.
Other mistake: Hawkeye reads the propaganda flyer, he says. "Give yourselves up, you can't win. Douglas MacArthur." Trouble is, the papers are all advertising for a flying company called Ace Eli.
Other mistake: Hawkeye loosened the nut and locking ring, but after lifting the assembly, it was obvious that these were steps used only to heighten tension. There was no locking device of any kind between the tail and body of the bomb.
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