During the Black Temple scenario, there is stage where you have eight minutes to loot as much treasure as you possibly can from the Den of Mortal Delights.
After the eight minutes are up, the treasure disappears and is no longer lootable. You are supposed to make your way to the end and appraise any treasures you might have found.
If you die after this point in the scenario, you respawn at the Reliquary of Souls. All of the mobs associated with this stage of the scenario respawn as well, along with all of the treasure in its lootable form.