Grand Dizzy's elevator
Grand Dizzy's elevator, on the fourth floor's far left, won't move, and its key isn't anywhere in the village.
Nudge 1Where to look
The village isn't the only place with elevators. Somebody took this key far away, underground.
Nudge 2A stronger push
The key is in the diamond mines, near the elevator control machine.
Show the solutionThe whole answer, with a video
Bring the key for Grand Dizzy's elevator back from the mines (The mines' elevators don't work), stand in the middle of the elevator's car and drop it. Up it goes to Grand Dizzy's landing. If you later come back to the fourth floor from below, stand under the elevator: an idle elevator comes down to Dizzy by itself.