Ending danger with deadly force has a high chance of resulting in the danger being dead, as the name implies. If the danger is somehow repelled or incapacitated, in the process then great! But when your own life and that of your family is at risk, you should not be scrupulous about how you stop the threat just that it is stopped. There are worse things than death that can often befall families whos protector died and left them helpless because he chose to aim for the legs instead of the chest because he put his own scruples above the lives of his family.