I do not think pages were numbered 1-6000. I think there were multiple documents, so you would need to do something like:
1. Split all the pages into piles for page 1, page 2, page 3, etc...
2. Look at highest page pile first, because it would have least number of documents, work backward through page piles searching for matching previous page until you extract all of the pages[0] for that document.
[0] If pages were heavily blanked out, identification might have been difficult.
Back then it wasn't likely. Today? If the NSA has secure rooms for viewing confidential documents that can not leave the room? It seems pretty darn likely it is a faraday cage. You think they don't know what they're doing? Or don't have the money in their budget?
In this scenario, leaving with or otherwise distributing a copy of the document would be equivalent to walking out the door with the original. Do you really think the NSA wouldn't be able to prevent that from happening?
I didn't think the NSA would be hopelessly humiliated by a lone syadmin currently residing in Russia to protect himself from a lack of due process, but here we are.
Snowden was considered an insider. Here a person considered an outsider would be in a controlled environment with the specific purpose of restricting the flow of information.
1. Split all the pages into piles for page 1, page 2, page 3, etc...
2. Look at highest page pile first, because it would have least number of documents, work backward through page piles searching for matching previous page until you extract all of the pages[0] for that document.
[0] If pages were heavily blanked out, identification might have been difficult.