Because, in her view, the previous failure to kill Emperor Ni was entirely due to Su Chen.
As Emperor Ni recovered from her injuries, it was certainly impossible for Gui Ji to suppress her again, especially since the refined Elven Source attack could only be unleashed once.
The two attacks collided fiercely in an instant. If this had happened within the Purple Tribulation Fox Clan, Su Chen would have surely managed to kill her, but his current strength could only maintain two-thirds of his peak state.
Chapter 312