You were walking in the woods around one day, when you stumble across a random electro-mechanical door just... standing by itself. Curiousity hits you, and you open the door. Instead of seeing the trees on the otherwise, it instead reveals a metallic chamber, with grey floors and white walls. There's an identical door inside the chamber, to the left.

You go to that door, and find a larger chamber, with a shelf of lockers and 8 more doors all around the room. You hear the clanking of metal.