Gan Ni didn't die, even though his skull had been shattered.
The injury was, in general, similar to other cultivators of the Rule Integration Realm who had lost an arm—serious, but not fatal.
This had to do with Gan Ni's special cultivation technique and his racial attribute.
With Chen Fei's discerning eye, he naturally noticed Gan Ni's condition right away. Shattering Gan Ni's skull merely quieted him; that was all.
Ignoring the screams of the Soul-devouring Worms, Chen Fei turned his head towards Ran Bin and the others, who were now close to a hundred miles away. That was close enough distance-wise.
The next moment, a black gleam flashed across Chen Fei's pupils, and Ran Bin and his companions disappeared, including Gan Ni in front of Chen Fei.
Chen Fei took a step forward and similarly vanished into thin air.