Tomb Robber

I played through the scenario. After clearing the surface, I couldn't find a way to get into the Necropolis... The two-way portal (with an indicator) is inactive, and I can't enter the Necropolis because of the blue-locked guardians. When I try to teleport using a cheat (to the only spot on the surface), a message from Hafiz appears, saying that he has been in the Necropolis... And when I try to proceed further (after removing the purple key, I think), and go through the second two-way portal, I lose...