>>723690550 (OP)
At a certain point, The Killer recognized her as its metaphysical counterpart, its dyad, and thereafter was not only not trying to kill her, but actively guiding her along to her (or rather, their) destiny.
As for how she survived the other stuff, her counterpart nature to The Killer obviously counts for something, but you could just handwave it as luck. After all, in the inversed new-world, the Killer BB comes for her and she still manages to survive.