Actually, Haruka said she found a key in one of those easter eggs they had laying around. She tried it in the door on the floating island. Don't know if you've been up there. [Seeing as you kind of have to be able to fly or air walk or teleport or have someone who can do something like that take you.] But there's this random free-standing door in a garden up there. I guess when it opened so did everything else. As for the accidental. [She gives a little shrug.]
You seem pretty curious and invested in the whole figuring this place out thing. Have you thought about joining the Investigative Team and working with us on it?