I think the answer for the majority of gun owners is when they come to YOUR house, to either inject you or your family, or to take you away to a "quarantine" camp. At that moment, in the case of forcible injection you are being assaulted with a deadly weapon. If they are trying to take you away, you know you will never be seen alive again, so there is nothing else to lose. That's when you are completely justified to defend yourself and your family with deadly force.