you do not shoot a person running away, thats murder, there is no threat. Thats the point, the gun is to remove threat, if you show it and he runs you can not shoot. Again threat is removed. now if he has broken into your house, its dark and you see him and shoot, this is fine, just make sure you are not shooting your family member as has been the case a few times. so better to announce. and if not identified and not backing out leaving/running shoot.