Let the narrative railroading begin! lawful good characters down bad!
How, exactly? If you don't get her out of the pod, she'll turn up later, after all, it wasn't possible for quite a while. If you choose to rescue her because you want her for the cambion fight, that's not a narrative railroading, that's a player choice, and if you wind up having to use the tadpole to do it, it's still a player choice. In this instance, the game taking control of the character, and using the tadpole would be railroading. I'm not seeing anyone stating or claiming that, so no?
