This one may require some luck, I am uncertain. To succeed at this challenge, walk left twice so you are on top of the 1 tile water. The Gather should get next to you safely on the left. Then walk diagonally and head into the left hallway with it chasing you. Enter the room with all of the Pickpockets, and walk straight across the room into the hallway to the left. After entering this hallway, the safe Pickpocket should take the doorway next to you. Start attacking the Pickpockets so they drop Gitan Bags. Continue to kill off any Pickpockets that move adjacent to you, as you want numerous Thiefwalrus to pick up these Gitan Bags. After the Gather moves next to you again, proceed to walk left and then up and around the hallway. Then head into the big room and walk down to the lowest hallway exiting toward the right (below where you entered.) If done correctly, you will see Thiefwalrus' in the room with the Stairs, and they will move to avoid you which will in turn block off the Death Reaper from reaching you. Simply walk to the stairs to finish.
