OK. If it were me, I would slip away from her without making waves. Because I could not take the chance of being tied to someone who is investigated for cruelty, the odds are that will come to haunt you in the worst of ways.
Since doing rescue on your own is really way too much to handle is there another organization you could choose to deal with? That would be my first step. Even your local SPCA might be a place you can volunteer with. If they can find foster homes they might need to put less animals to death. And Petco will no doubt be willing to offer those cages to another local group because I am sure they want to help the animals.