The organ's puzzle plays out like a game of Simon. Mickey must repeat the short melodies that the Pipe Organ plays by jumping on the highlighted piano keys. Doing this successfully allows Mickey to progress to the exit by platforming on the valves behind the organ.
Alternatively, if Mickey thins the organ's toon keys, it will become enraged, block the normal exit, and send out enemies to attack Mickey. This marks the organ's quest as failed, Mickey now has to activate the pressure plates behind the toon walls on both sides of the room, climb on the floating tables, and get to the exit from the balcony.
The entire puzzle can be avoided with some carefully-placed jumps since the exit projector is always active, but Mickey will not have completed the quest and will not receive Donald's Torso after returning to Bog Easy.