Per 
SCP-XXXX
Item #: SCP-XXXX
Object Class: Safe
Special Containment Procedures: SCP-XXXX is to remain in Vault-12, and should not be entered without approval from the current site director.
Description: SCP-XXXX is a wooden door. Upon stepping through SCP-XXXX, an individual becomes superposed between an unknown amount of realities. Said individual will remain in this state until someone checks which reality they are in, destroying the other realities in the process.
A better explanation of this anomalous effect can be seen in the "Schrodinger Cat" thought experiment. If a cat is in a box, an outside observer would be unable to know if said cat was dead or alive without opening the box. As such, until the box is opened the cat is both dead and alive. This special state of being collapses upon opening the box, wherein the cat is either dead or alive.
Similar to how the cat can be both dead and alive, subjects who enter SCP-XXXX exist in multiple realities at once. Furthermore, like said cat, a subject inside of SCP-XXXX will only exist in one of those realities when someone checks their location. This can occur by communicating with said individual, or by reading transcripts of past conversations.
Addendum 1:
The following is an experiment log recorded by Junior Researcher Grey. It should be noted that this experiment was originally supposed to be performed by Dr. ███████, while Ms. Grey observed and helped when necessary. However, due to a last minute familial issue, Dr. ███████ was unable to perform this experiment, and authorized Ms. Grey to perform it in his place.
Note from Dr. Grey:
I am so excited! My first SCP! I cant wait!
Date: September 8, 20██
Time: 6:38 PM
Procedure:
D-3903 was given a portable communication device, and was instructed to enter SCP-XXXX. Below is a recorded transcript of said device.
D-3903: Alright, I see a red carpet. There are stone walls that seem to go on forever, lit by torches placed periodically. Behind me is another stone wall, and above me a stone ceiling.
Dr. Grey: So you're in a hallway?
D-3903: Yep. I guess I should start moving forward, try and find a way outta here.
Several minutes of footsteps can be heard
D-3903: So why is it Foundation policy?
Dr. Grey: Huh?
D-3903: The name policy. Why do you have to call me 'D-3903'?
Dr. Grey: Oh. If I were to make a guess, I'd say its so that way we don't get too attached to the D-class.
D-3903: Because we will be leaving in a month, or because the experiments the Foundation performs are too dangerous?
Dr. Grey is silent for a few minutes
D-3903: Ms. Grey? Did you hear me?
Dr. Grey: Yeah… I heard you.
D-3903: Whats wrong? You didn't respond to my question.
Dr. Grey: I… I can't do this…
D-3903: Do what?
Dr. Grey: Do you know what D-class means?
D-3903: I assume it is some sort of security clearance code, or something.
Dr. Grey: No. It means disposable. The Foundation doesn't care if you die, just that you do what you're told.
D-3903: Ha, makes sense I suppose. I mean, they are offering death row and life sentence inmates an opportunity to be free after just a month. I guess-
Dr. Grey: No.
D-3903: What do-
Dr. Grey: That's not true. They aren't going to let you free in a month.
D-3903: But what about Fredrick? Hank? Jessica?
Dr. Grey: Dead. Terminated. Killed after a month.
D-3903: So that's what you meant by disposable… I found the door… I'll let you know what's on the other side.
D-3903: There are several pyramids... | There is a mountain...
