Back at home, Li Yifei couldn't immediately attempt the treatment because only Su Mengxin knew about his relationship with Xu Shanshan. Even though other women belonged to him, the affair with Xu Shanshan was not something that could be publicized. Even if everyone wouldn't deliberately talk about it, who knew if someone might accidentally let it slip? That would be troublesome.
So Li Yifei and Xu Shanshan could only try in secret, which presented some difficulties. Firstly, it was best for them to be together near Xu Yingying to more directly observe her responses.
However, even if they could find an excuse to be with Xu Yingying, they didn't dare to proceed with their plan. Xu Yingying was in a self-imposed isolation; who knew if she could also hear sounds around her? If she were to suddenly wake up while Li Yifei and Xu Shanshan were in the midst of those activities, it would be a disaster for them both.