Gu Mu started to cry when she realized that Gu Man had betrayed her and Mei Shu. The two of them acted as tyrants because they thought that Gu Man wouldn't dare to complain against them, in fact, he indeed stayed quiet.
Because of this Mei Shu and Gu Mu were emboldened. They never thought that Gu Man was actually waiting for the right time to file a complaint against them! They thought that the reason Gu Man stayed quiet was because he cared for his wife and wouldn't want her to be thrown into the prison but looks like they were too conceited. This mer was even more ruthless than they expected!