You have done it! As I promised, here is the key to the Inner Sanctum.

Lightning Field? The Grandmasters would never shield the entry to their Council Hall in such an offensive manner! This Keystone opens the mechanical locks of Inner Sanctum gates, but this unholy energy field you describe is another matter. Regarding this impediment, I do not know what advice I can give. Perhaps someone in your time who has studied such things can provide a solution.