The people involved are surely a key element. Who were they? What were their motives for being part of the Sanctum story? Were they seekers of something, like knowledge or power? Their actions and relationships would shape the story a great deal.
One possible key element could be the location of Sanctum. If it's a physical place, its geographical features might play a role in the story. For instance, if it's in a remote area, it could have affected how people interacted with it.
Another key element could be any mystery or enigma associated with Sanctum. Maybe there were unexplained phenomena in or around Sanctum. This could attract curious minds and drive the plot of the real story. It could also be that there are ancient secrets hidden in Sanctum that people are trying to uncover or protect.