My first murder was earlier today. I'd spent a good few hours in Cherno gathering supplies, managed to get an M16A2, an M1911, insane amounts of ammo for each of them, plus all the medical supplies/survival materials I'd need for the whole game. I'd left Cherno and headed for the Balota airfields, and logged out in the ACT. I log back in, and below me is a player with an 870 flashlight. I call out "Friendly?", and he doesn't respond. I walk down the stairs, he opens fire on me (the stairs take all the shots). I had my M16 on Semi-Auto, so I spam the fire button, and put at least 10 rounds into him. Right before he died, he hit me dead center with a slug, and put me down to 4k blood. I bandage up, and another guy comes up the stairs, saying "Hey, I heard gunfire, you okay?." He then offers to give me a transfusion with one of my packs, given the situation it'd be better to trust the guy than shoot him. He pulls out a blood pack, and a blood pack only, gives me a transfusion, and goes on his merry way. If that man is reading this post, thank you so much. To the person who opened fire, I hope you learned a valuable lesson. Stairs block bullets. To answer OP's question, I don't really feel guilty for killing him. He fired at me first, and if it hadn't been for those stairs, I'd have been dead.