Well maybe we could free them but they find their own way out? I know that might seem rough, but at least if we free them there's a chance they could escape. That's what Parum would want anyways. She can understand that maybe they can't bring all of them to Greenest, and frankly they might not be able to even get back home on their own, but she can't just leave them caged up. And pragmatically speaking, if the cultist do notice the other slaves escaping, it might give us an opening as everyone is scrambling to capture the freed slaves.