Archives door number prediction
The archives door numbers are shown to have different starting letters from A to Z.
I predict that, each letter will have 50 rooms. Correct me if I'm wrong, but this can be supported by the fact that none of the door numbers shown in any of the teasers exceed 50, the highest door number ever shown is 48.
So there will be A-001 to A-050, but after A-050, instead of A-051, would be B-001 and so on. This would continue until Z-050 which would be the end of the archives, making 1300 rooms total