[ ] Use your spare Power Stone to save any Dwarves left in the ship
This will be achieved by supercharging an Illusion to make it loud enough to be heard throughout the ship, despite the water and metal muffling you. This will tell them all to douse any lights they have on them, making it safe to enter their compartments and retrieve them. Mathilde will only enter compartments that return her knocking, which would signify that there's someone inside who would have heard and followed her instructions.