After gaining Madam Lu's trust, it was just convenient for her to flex her muscles. Helping Madam Lu poison the concubines of the Lu Family and gaining her favor in the process, what a good deal! It's just that they did not know why they got exposed.
This mother and daughter, who knows how many outrageous things they've done on behalf of Madam Lu. Madam Lu's situation is somewhat similar to Miss Du—despite having the support of the rest of the Jie Family, Miss Du never went after the favored concubine of the second young master of the Jie Family.