Destiny 2 Black Armory – Watcher Locations Guide in the Leviathan Underbelly for the Mysterious Box, Key Mold.
In this guide we show you how to get to the Underbelly and “Harvest parts from every Watcher in the underbelly of the Leviathan”.
You need the key mold for the Mysterious Box, which we’ll explain to you here.
To collect all the parts from the watcher, you do not have to find and defeat each Watcher, go into the engine room to complete this quest. To enter the Underbelly you need to activate the levers in the following order: 1-5-3-2-4-6
My apologies it did work. Had to equip both mida multitool and calus to help speed.