"Why should I let him go just because you pleaded? Who are you? Aren't you the one who encouraged them to come rob us. Then all of you should suffer the consequences of your ignorance." Leng Pan didn't show an ounce of mercy just because the woman was pleading.
They were only pleading for mercy because they realized that they were no match for them. However, if she and Lu Zhen didn't have the strength to protect themselves and the family, then they would have suffered humiliation and probably death today.
Why should she show mercy to someone like that? Moreover, the person pleading had no morals at all. She didn't hesitate to betray her husband for some food, what was stopping her from doing it again in the future for something less significant?
"Please, I know I was wrong, let it go just this once. We won't dare to cover your supplies again. Please." The woman continued to plead.