Dai An continued to act as a parasitic spirit inside Bing Shi's soul as she used to with everyone else, forgetting the fact about how much the traumas she got 'used to' and viewed as 'normal' were affecting Bing Shi. Thus the reason why Ziek reacted as he reacted.
Ru Quan touched his temples with closed eyes as he curled Dai An's middle finger back to its rightful position within his palm, "We will be able to prevent your disappearance as soon as you agree to join my soul. You can gain my powers together with my knowledge and meet up with Bing Shi whenever you want, okay?"
At the same time, he understood how Dai An didn't have a choice but to stay as a spirit. If she remained as a soul together with Bing Shi together, the faster she would get devoured like the rest of her lifetimes in order to retain Bing Shi's identity, especially now that Bing Shi was going through her godhood.