This mistress was fed up with how her boss treated her that she had to punish him. She chose to dominate him with her wrestling prowess. That is why she had to act as cruelly as she was able to. The mistress went out her way to wrestle him and make him fear her. He did not expect her to be that good at wrestling. But she was good at martial arts and she used it to wrestle and defeat him. He begged her for mercy before she quit her job.