I dunno, these things were used as underground windows. I don't think they're half as complicated as that if they just stuck 'em in a frame and called it a day.

[He rests his hand on his chin, giving this some thought. Well, if Rei had that much faith in this Hiro person...]

... but okay, fine, let's get in touch with this guy. May as well get to the bottom of this as soon as we can, right?