You certainly need to be aware of your backstop but in Florida and
most states with a reasonable law you are allowed to use deadly force
to stop someone who posses the danger of causing imminent bodily harm
to another and a guy in tactical gear shooting into a building would
qualify. In fact the guy who did shoot this prick did it with a rifle
and managed to get through his body armor. My .308 would have no
problem at all with soft body armor.