"You must."  Alyssana's tone did not encourage debate.  "It's one thing for him to toy with ladies' feelings, and quite another to reduce someone to little more than a vacant-eyed fool.  He's lucky the effect wasn't permanent, or I would be having a few very pointed words with him."  She took a breath, reining in her anger.  Walter was hardly at fault for this, and while she did mean to have a word with Finnegan she didn't think he'd respond well if she pushed him too hard.  Better to simply remove the temptation -- and that's why she was speaking to Walter.

Already he'd confirmed her suspicions, that Finnegan was at fault.  If that wasn't the case, Walter wouldn't be trying to protect his brother.  Perhaps she was taking advantage, just a little, but she was used to Christopher's wavery moral compass and the need for a firm stance.  "I need to be sure he won't do something like this again.  It's a terrible violation of a lady's free will."