Shen Minyao did expect that Liang Sisi would react this way. However, she wasn't worried that Liang Sisi would reveal what she had seen that night. After all, Shen Minyao was able to reappear in front of the dormitory in a mere second, allowing some people to see her entering the building.
It was Liang Sisi's fault that she had schemed against the fox woman. If she didn't dare to harm Shen Minyao and threatened Li Fei'er's and the other's lives, Shen Minyao wouldn't resort to pushing her to insanity. She was able to use her powers to manipulate Liang Sisi's mind now, after all.
By now, Liang Sisi should start hallucinating, seeing her dead best friend and hearing voices that weren't there in the first place. So it didn't come as a surprise to Shen Minyao when she heard from Li Fei'er that Liang Sisi had confessed about the crime against Bai Xinran she committed, but it was obvious that she was also not in the right state of mind.