While doing a thorough exploration of Elona, Lorenzo needed to go inside the Gandara. It turns out he also needed to perform the mission there. After inviting Olias (minion master), Gwen  (interrupter with Ward Against Harm), Magrid the Sly (Barrage), Eve, Kihm, Mhenlo and Gehraz managed to finish the Pogahn Passage mission in Hard mode.

Regretfully, it turns out Lorenzo has already explored the inside of the fortress thoroughly.