If the Green Frost Sword were still around, during the Crossing Tribulation, she might still have fallen at the third layer of Heavenly Tribulation. Because at that time, the Green Frost Sword would have become one with her, contradicting her Sword Dao, and it too would be harmed by the Heavenly Tribulation.
To truly achieve Taoist Heart Perfection, she could only do so by personally severing her past Heart Demon, severing her emotions. Only then could she be truly Fulfilled. This was instead of extracting a strand of her Divine Soul to merge her emotions into it, transforming it into the Sword Spirit sealed within the Green Frost Sword, leaving a sliver of leeway. In some sense, this itself was a shortcut. The Heavenly Dao is impermanent; any shortcuts make one unable to glimpse the profundity of the Great Taoist. No wonder Mu Hongyuan and the others said that she herself was the Heart Demon, and she must sever herself to truly enter the Dao.
