The more I think about it, the more I am forced to conclude that striking a meaningful blow against Uzkulak is... just not something Mathilde is equipped to do. As Boney pointed out, the skaven have been at war with them for a long time; Mathilde cannot expect to
significantly improve on the skaven's performance after having been on the scene for just a little while.
I think people are very heavily underestimating the competence of the enemies here. This is the sort of thing Mathilde spent weeks pulling off against Orcs, and people are talking about her doing it in a matter of hours while she's in the neighbourhood against two of the factions that most often pull this kind of thing against themselves, and they're already on high alert and extremely honed by the tricks and schemes they've been pulling on each other for forever.
This is something we'd have to spend a long time planning and preparing for, and... for what? To get at max a couple hundred slaves, which will probably include no small portion of skaven and other Order-faction undesirables, out of Uzkulak and into the Great Skull Land? With what supply line? How do we get them to something approximating safety? We'd need hefty logistical support to feed and transport that many people, and I don't see that happening any time soon.
That being said, I am also not content to shrug. Mathilde may not be capable of meaningfully harming Uzkulak, but there is a
different slaver faction we do have some ability to fight: the druchii. I want to go on the elfternship soon and fuck up some dark elves with the Shadow Warriors. Fewer druchii, fewer corsairs. Fewer corsairs, fewer slaves taken at sea.
That is something we've got an existing angle on, and hopefully we can impress the Shadow Warriors enough to make it a recurring thing. Unlike jailbreaking an unknown quantity of people of unknown trustworthiness from the most anti-theft faction in existence over a thousand miles from safety, this is a blow that Mathilde has the competencies and contacts to really
accomplish.
(But also, if circumstances on the return trip permit, I will absolutely vote for spending every red cent we've got in the slave market.)