Four bullets are missing from the box; three empty shells and one primed bullet are sitting there. She has no chambered rounds, though she isn't following proper trigger safety rules. Weeeeeird.
I'd say the only error is the number of rounds that box holds. The AW50 feeds from a 5-round magazine so it doesn't make much sense to have a 21-round box of ammo. (Doesn't mean the military would never do stupid stuff like that though.) Presumably there is supposed to be a chambered round, and Shanghai's got her finger on the trigger because she's about to fire.