Actually, there aren’t any Buddhist “rules”. You can do whatever you want to. You can lie down on a railroad track in front of a speeding train if you like. If you do, a Buddhist is likely to have compassion for you and try to help you out before the train comes. Buddhism is more a matter of suggestions based on information given by people who have given a lot of time to contemplating the true nature of the universe. It’s not as though if you lie down on the railroad track anyone is going to smite you. If you kill, its going to have harsh consequences just like if you lie on the tracks before a speeding train will.