I'm convinced that Fyrakk bathing in shadowflame is why they opened up the way to Aberrus as Shadowflame is the energy powering the facility.
So it's all part of their plan, Fyrakk waking the ancient Djaradin and binding them to their oath, and letting the sunderedflame retaking Aberrus.
If anything I'm surprised by how Fyrakk was able to keep his head straight because he's shown as hungry for revenge and had many opportunities to deviate from the plan but even after bathing in shadowflame he stays in line and uses the djaradin and his minions as deterrent.