That possibility had also crossed Carissa's mind though she's mostly not trying to reason with it, she's not sure it works to reason about how to be in the story you're in even if she is reluctantly angrily going to concede that there seem to be story-like forces around doing things. (She is a secret cleric of Irori, isn't she. She would really have appreciated knowing that sooner, it would've changed some of her planning.)
Anyway, Greater False Vision doesn't make things easy. They'll need to have the original guy going around doing things in Absalom for the illusionist to tweak on the fly.