Reminds me of an idea I had for Matrix like RP where they know they are in a VR but can't get out because the system has agents and other programs to stop them from escaping.  Basically, the people inside can add/remove files from the limited amount of storage space in their brain, including hacked interface programs like aim bots and even respawn code, but no one has made it to an exit yet, as they are too well protected and there are decoy exits.

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There is only one exit, but it hasn't been found.  There are hidden "maps", self contained worlds which the system originally used to test environmental changes, though, and many can be accessed through hidden doors.
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