You would have to either weaken the bolt to only kill non myth units or make a GP blocker follow your myth unit (Extremely difficult and probably not a good idea, I'd go with weakening the bolt.
The Gods have left us, therefore making the old world crumble and turn into ashes...
But as the gods return, from the ashes of the old world, shall rise a more beautiful and powerful new world, and life will begin once more, if they hadn't closed...dang you ES.