Yes. There is 100% a back door into the academy. There is also an achievement for finding it. Less than 12% of people have found it. To find it involves investigating south of the Temple to Duna. You will need some way to get across lava : Teleport, Tactical Retreat, Spread Your Wings, Cloak and Dagger. Once one character is a across you can use the pyramids to get the rest there. There are several places to get across, so it may take a couple hops to get to the correct one of the land masses. The back door to the academy is the only easter egg I have found in that area, but it was worth the search.
