Right before the attack destroyed her, Sterlena used the entirety of her power and her new Law, the Heavenly Destruction Law, to envelop a tiny fragment of her core that she teleported using the crack in space.
A part of the violet bolt of lightning branched off to chase after the fragmented core. Though, as Sterlena had already infused the entirety of her power in the Heavenly Destruction Law surrounding that fragment, it was able to survive the attack and fall off from the God Realm, falling into the Mortal Realm where it formed a Danger Zone.
She barely survived the attack. And it was only because the fragment of her core that she broke off was too small, so the violet lightning that branched out was weak. After infusing all her power into it, she managed to ensure this fragment remained safe.