He most likely will start arguing with the aggressor, at least the first some minutes.
But all this time the child learns to transfer the violent feelings to game.
He directs on you the toy gun and speaks: A bangbang, I killed you.
It is not necessary to abuse it for it or to learn that it is bad.
He already knows that it is impossible to hurt close people, but can unburden the heart in the form of game.
It partly speaks why children love cruel stories.
Moreover, the child playing war will be able to become the kind person rather, than what accumulates hostile feelings, in any way them without stating.