Temperature's way off the charts in here. This must be the power source for the Storm Machine!
― Bentley realizing how the Storm Machine gets its power[src]
Sly found his way inside a place that had temperature readings way off the charts. Bentley claimed this to be the power source for Raleigh's storm machine. In order to gain another treasure key, Sly had to navigate through the lava-filled place, fighting off several walrus guards and avoiding several furnaces.
Upon reaching the end of the area, he had to break open the glass blocking the conveyor belt that led to the key. By activating the spinning wheel, Sly managed to get a large lava rock to roll down the belt and bust through the glass, allowing him to run along the belt and claim the key.
I'm unbeatable! No code can stand before me! It's got to be 5-7-9!