I think it is trying to say that someone from the army is on break and eating a sandwich
Explanation:
the army was done after a long day, one person went to have a break, but they forgot to put the guns on saftey. They also forgot to make sure the gate was closed. They went and made sure everything was fine and thought oh it is I will just go and eat so they ate a sandwich.
The answer among these works that features a flute with a delicate, "breathy" sound in a relatively high register is Concerto for Orchestra by Bela Bartok.
