A week without discuss. The Codex is just not the same.
Anyway, the more I think about it, the more I become convinced that it is not in our interests to let Madam Nie talk in our situation, even if we take her captive.
The Twins have said that they are ready to beat the answers out of her, if need be, and that is to be expected from a pair of fighters with a fiery temperament facing a dangerous opponent, but do they have what it takes to question her when they finally defeat her? What can they do to loosen her tongue? Rough her up? Subject her to a slow torture? Of course not! Those girls are worse idealists than even Yifang. Then what? Threaten to kill her so that she would no longer poison her father? Without a trial? Withous any solid evidence to their claims? One of the reasons they want to resort to violence is because they have nothing conclusive on her except for the feeling that something is not right. How would they ever explain it to their father, or to the rest of the world?
Now we could probably do all of that and worse, but we sure as hell wouldn't, because it would be simply wrong suicidal to do so with two upright orthodoxes and Bai Jiutian watching. With the witnesses around, we are limited to the methods they give their consent to.
The girls are operating with a preconception that a cornered villain will tell everything to save their hide if you threaten then, since the villains have to be cowardly and disgraceful, but it does not work like that, if only because the truth about Madam Nie is far more damning than some vague doubts they may have about her activities. There is no way Madam Nie will tell them everything, and there is no way to force her that would be acceptable to them. Even worse, though, is the possibility that they might consider whatever 'confession' their mother gives them as truth, because that is what a defeated villain is supposed to do when they seemingly have no other way to save themselves. Madam Nie can really let her imagination loose, and they might swallow her story. She can even say she was in league with us, Man Tiger Pig, and the girls might believe her because as far as they know, we are after the same manuals and up to no good - hell, the first thing they accused Madam Nie of was infidelity.
She only needs to turn the girls against us and have them take her to Nie Wuxing 'to expose her vile plots'. We know what side their father would choose - have already chosen, in fact.
Manipulating people to Manam Nie is what fighting is to us. It is her element, her gift, her call, even. As well as I am sure that we can outperform her in combat, I am also sure that she can beat us in a game of intrigue.
Maybe the best move is not to play, then? Maybe just not giving Madam Nie an opportunity to open her mouth and poison people's minds would be a small victory?