FAQ text: For me, I would say that this is pretty unequivocal, no matter how many ARM/BTS saves there are, it only counts as doing one wound when applying the State: Dead (which can only be done once anyway).
Cut and paste from the very next question in the FAQ. What happens if the target of a Protheion user fails more Saving Rolls than are needed for it to enter Dead State? For example if an Unconscious target fails two or more Saving Rolls. Any additional failed Saving Rolls will have no effect, and will not give the Protheion user any Wounds.
Yes, but gaining multiple power-ups depends on inflicting multiple Wounds, and the FAQ just says the attack counts as inflicting a single Wound for the purposes of Protheion. Nothing in the FAQ would permit triggering the rules for multiple power ups in a single attack.