Sister Ning had no idea who was the one who passed down this order. All she knew was that the warden of the prison came to her cell and told her that they would be sending a new member.
The warden asked her to deal with this new woman rather 'carefully' and thus Sister Ning agreed at once. After all, she had been doing this for ages. As she was locked up in prison because of murdering someone, she knew that the chances of getting out of there were impossible.
Thus, she would do the bidding of the higher-ups. As long as they told her to do something, she would not refuse, and in exchange, the higher-ups would give her small benefits such as cigars, meat, and sometimes some little things for entertainment.
Thus, when they asked her to teach Luo Huian a lesson, Sister Ning did not refuse. After all, what could a young woman who grew up with a silver spoon with a diamond inlaid in it do to her?