I'm very curious as to how this works at a basic level. Perhaps a 'positive-control' system in which he has to send a signal to some clandestine web service every 24 hours to prevent the keys from being released? Does he have an Arduino board strapped to his chest detecting his pulse? Or has he simply entrusted some mechanism to somebody else, who can determine whether the keys should be released depending on the nuances of the situation in which he is harmed/killed?