Yeah. The idea is basically "and then the players were the ghosts". Then when they think of what they remember, being normal kids and all, well, that's how it begins.
Somehow, the SCP-ish properties of the building make it make more sense. The school feels abandoned for longer than it has been, it's actually full of the ghosts of missing kids on Halloween, and it's not a tourist magnet already? Not even thinking of the masqueradea breach it means for a real-like world. No, it's a one-time occurrence, and all who entered it in any reality will get lost in the maze. In the other realities, the building's life was different every time, some versions were even located in other countries, and/or at other times. Some were still active at the time of the mix-up, others had been destroyed, some have milk cartons with missing child advices, some have paper clippings neatly stocked in a folder, detailing stuff about missing kids, missing kids statistics, notes about how <Teacher X> loves how kids disappear, then other notes about how horrible it is and half-begun amateur investigation to find some back.