Bonus Loot
Pick up the ground spawn bag near the quest giver, combine all 10 pieces inside of it, you can only do this combine after finishing Fish Eyes in the Dark
The above statement is incorrect. I have not done Fish Eyes in the Dark. This is what I did do: I completed Pieces is Pieces without the bag. When I turned in the 10 pieces and completed the quest it gave me a 16h 3m lockout timer. I picked the bag up, and ran around and grabbed the items again. I hit Combine, and it gave me the Deep Caverns Collector's Case. You don't have to do the quest twice, just once, and then use the bag and re-collect the items again and hit combine. It turns that into the case.