Obtain the 3 medallions from the storage box and place them on the statue pedestal to make the statue drop the key.
Inside the object MedallionPuzzle there is an InteractionWithItemUse object which expects the 3 medallions. These will enable the medallion mesh on the pedestal. The InteractionWithItemUse is also set to remove the objects from the player inventory.
Every time a medallion is added, ItemSequencePuzzle.Add gets called on MedallionPuzzle. This puzzle expects the 3 medallions in no particular order
When the 3 medallions have been added to the puzzle, OnSolved gets called, which plays the cutscene.
The cutscene plays CutSceneObjectDrop, which enables the ground PickupKey in the animation itself.