Extend the Story - Add a Room

You begin to search the next room. Again, nobody is there, but the room looks like a battlefield. You know people must have been here recently, because fires need food, and the wood doesn't last forever.
You memorise the room, and begin climbing the stairs, the naval officer in the lead.
Above the stairs is a door. The naval officer listens carefully, and decides there is nobody in front of the door, or in the room.He also applies something that will make the door silent when opened. You're curious on where he could have gotten that, but don't push it because he scares you.
He opens the door, and he seems to have been right. Nobody was there.
This is proven false when he's shot and killed and you're held gun point by a man in his late 30's.
"Prove you're innocent."

"Are you the only one?"