The Farseer was one of the most competent scryers of the Red Collective.
She was not able to observe the entire headquarters due to complications deeper within the planetary base, but she was still able to catch plenty of glimpses elsewhere.
They did so with the help of formation anchors that had been secretly planted underneath the surface of Jotunheim.
The Ascended Giants did not have perfect control over their icy planet. The collies successfully snuck formation anchors and listening devices all across the planet, though they did not dare to bring anything too big and powerful for fear of detection.
The compromised personnel still retained their skills and knowledge even if their views had changed.
In any case, Andrea Vos along with other scryers would continue to monitor the Ascended Giants as they prepared to participate or witness the ritualistic challenge.