the witch family must burn
I have a feeling they are, right now. Like, "oh yeah, but that's minor compared to my profits that fire will lead to. After all, I purchased all the lumber beforehand, and with the entirety of the city burning down there is going to be a lot of houses that needs to be rebuilt. 'eh?' you say? Why, afterall, if my shop burns then there is no way the rest of the city won't as well?"
Be that by military going around putting her guild's shops to the torch, or more likely, by the chekovs gun that is petroleum being used for some nice arson. Maybe even put as having "doused the shop in karmic water that returns fire to whoever set it", but more likely simply that the stores of it in the shop will make the fire large enough to spread to the next house - and so on with strategically placed petroleum warehouses in the path towards the guild's areas.
That said, I know my feeling is going to be wrong. Because no way will author let their character do something so drastic with such a human cost. But it
would have been nice.