Vax reached for Percy's key, sliding the hard rectangle out from the paper. He faced it the right way and inserted it into the slot in the boxy thing over the door handle, and it beeped acceptance at them. Vax pushed the handle and swung the door open with a dramatic wave of a gesture, smirking back at Percy.

"I've broken a few of these," he noted almost proudly, handing the card and paper sleeve over to Percy again. "Still no idea what's going on that makes them work. And only your card will open up your door."