Do you need a metric [truck]ton of shining crystals for 4* items like I do?
Arcade, Iron Skull, T3.
First level is Decon Zone. Run to elevator; skip everything. (Could just unlock the treasure room and nothing else, but that's hard to do with an entire battalion of gremlins trying to murder you)
See if elevator takes you to Treasure Vault.
If you do not go to Treasure Vault, open up mission tab. Choose Arcade, Iron Skull, T3. (This way you don't have to return to Haven)
Repeat ad nauseum or until Iron Skull closes. You have 8 days as of this post.
(Could just unlock the treasure room, and nothing else, hard t do with a army of gremlins attacking you)
Bleh, grab a good sword, and a high health shield... and Run like the wind!!!!!!!
=D