.. What do I do with the stuff in the judge's box?

There are three items in here. The thing in the middle is a box of gold foil seals, which I would assume the gang was using to forge invoices. The thing on the right is a series of messages between two of the perpetrators, and now you know who the mastermind really was.

The electrical thing at the left is the thing you need to use to get the lift working again. But when you try to pick it up, you actually get a blueprint that shows how the gang was planning to move the stolen items.

As soon as you're done looking at the blueprint --

-- well, welcome to the real endgame, duckling.

How do I escape these chains?