That... makes sense. "Good point. If this is the work of a single person, there might even be pettier personal motivations. Sabotaging Ashari's position in the rebellion, perhaps." Or, now that Sulen comes to think of it, sabotaging them. They did interrogate several rebellion agents before turning heretic, extracting information that might have led to the death of others. Not exactly implausible someone might hold a grudge.
Re: Gerae + the rebellion