Board Thread:Updates and Annoucements/@comment-24588058-20170920030623/@comment-24588058-20170921001538

It's meant to represent Warehouse 3.

You're not imagining it wrong, per say. The hallway was really only there around the time of Warehouses 3 and 4. During the time of Warehouse 4 (my timeline, her idea), an (as-yet unexplained) event occurs which leads to the Regents deciding it needs to better protect the Eldunari. That lead to the creation of the door-change, with the help of an artifact. When they moved to Warehouse 5 (and the subsequent moves), the Warehouse felt the hallway wasn't necessary (since it was now a limited-access room that few people would visit), so it didn't form one.

Her idea makes me think that the access to the Eldunari can change between Warehouses to fit the overall style of the building. The spiral staircase (I think it was a spiral, at least) fits the style of Warehouse 13. It might change slightly with each Warehouse.