This is true, but since it has no engagement range, I would just move my model away from it (assuming I wasn't already engaged with something else). In order for a model to be "killed" it must be specifically must be dealt damage. That said, you could be the one to deal damage to it (from whatever means you have), and thus triggering "Explosive Demise". But if it were to activate without having been struck, it would simply die and be sacrificed. once it activates though, it's half life ability triggers dealing itself 1 damage. The ability doesn't claim that this causes sacrifice unlike its attack or Ramos uncontrolled explosion. I wish I had my card on me