You can kill quitly with any melee weapon or a firearm with silencers. Since, it's my belief that the "mallers" are the ones responsible for cleaning out the reserve armory, they may have found something else in there. Only thing is that the Army isn't big on the silent treatment. They like to blow things up.
I've worked the armory as an AF Security Force member and everything in there went bang. The one thing I do know, is that prisoners are the most inventive people in the world....
Anyway, who was the one to originally want a party and get drunk? I need to listen to that episode again. Seems that was the dumbest idea in the world, but could have been part of the plan.