Once you finish restoring Darbus back to normal, go over to the bomb shop and enter the building. Find and stand next to Barnes. Take out your lantern and he will quickly tell you to put it out. Then, stand somewhere else out of sight of him. He will stomp the ground and spray water all over you. It does not matter where you are in the building. You will always get water sprayed on you if you pull out your lantern.
