Our primary goal is to find the fragment. The Book of Briars pointed us to Brandon, so we do our best to find Brandon. We do our best to keep to the timeline.
Personally, despite my gut feeling and basic human emotions telling me the contrary, I'm not inclined to hate the Devoted. According to Reader they've fallen under some dark sway and it sounds like they've been betrayed before in the past. We can't let them get ahead of us, because in their current state they may never share it. I wouldn't object to helping them out once we move beyond the current trial though. I see no reason to be like them.