I'm just surprised they threw him in a dungeon at all. Sure, it's convenient for the plot, but it doesn't really seem in line with their attitude (or their plans).

But, maybe they have a schedule to uphold and they had to get everything lined up before they ritualistically slaughter Olrox. It's a possibility.
 
    

When evil spreads across the land, and darkness rises and the monsters roam. When the creatures of the night make beautiful music, and the things that go bump in the night go bump with greater enthusiasm. When the world is in peril and is in need of a hero...

These guys are, sadly, the best the world can hope for. These are the adventures of the heroes of CVRPG. They mean well, they try hard, and occasionally they do the impossible...

They actually do something heroic.