Apparently US police don't have tasers either. Because someone wielding a sword happens to be exactly the sort of target that tasers were designed for: a non-lethal takedown at mid range, of a suspect that would be dangerous if they got close. Someone waving a sword around cannot shoot you (if their broadsword can be waved one handed it isn't made of metal and is a harmless prop) which means that as long as they don't get within a few metres you are safe. No need to gun them down.