Bomb, some security will always be reactionary, it's like putting a monkey in a room that only has 5 exits, the monkey always gets out a 6th way. No security is 100%. I think bobby mentioned explosives in dogs, why not a pound of c-4 implanted in a human with the button in their button? Rear molar bombs?
I don't have a solution to this at all and it's getting harder and harder to draw that line