Visible crew/equipment: While Hawkeye's being questioned by the prosecuting counsel, we can see the curved chalk foot marks on the floor right behind Hawkeye's chair, such as when council asks where Hawkeye was when the camera was stolen.
Visible crew/equipment: While Colonel Potter, Margaret, and Father Mulcahy are in the mess tent, we see that BJ and Hawkeye arrive back at camp in the jeep, and when they walk into the mess tent the curved chalk foot marks can be seen on the floor under the table, between Potter and Mulcahy.
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