Help me answer this question. Son (5y/o) asks: "What do soldiers shoot their guns at?"

Context: Father is a veteran and now doing contracting.I tried to give out non-people-hurting answers such as "tanks" or "targets" but son was not convinced so I slipped out "bad guys" to which he replied "But that's too bad for them!" And I said that soldiers have other stuff to do other than shoot/combat such as giving aid and helping people.I managed to somehow change the subject saying it was already bedtime it's a big day tomorow, etc. Surely he will be asking the same question again and I don't know how to properly respond. My child's sensitive about these things, like I wouldn't be surprised if he becomes vegan because "it's a pitty to kill the cow."Thank you in advance. via /r/Parenting https://ift.tt/2AddGQq