When I recently played Nolani Academy with some other players I had to realize that many players still don't know about the Nolani Academy mission shortcut.
How to skip the final part of the mission
The final part of the mission, helping Rurik cleanse Rin from the charr, is usually considered the hardest part of the mission. Prince Rurik will run into an army of charr and often either he or your team will die because of his preposterous assault. No more!
After guiding Prince Rurik to the Great Wall you're allowed to pass it. After a cutscene you are on the other side of the Wall. Instead of following Rurik, go west and then, when possible, south. Keep right and you'll quickly find Bonfaaz Burntpelt, the final boss of this mission. Upon his death the mission is complete without any risk of Rurik being killed.
If my description is not clear enough, check this vid; the shortcut is seen at 04:10: Shortcut vid
Link for those who can't see above link: youtube.com/watch?v=eAxSYsUp2ek