It's when you push too hard and your finger pokes through the paper...

70% sure that means everyone dying and having to start on the last checkpoint.

When everyone dies and the "darkness consumes you." This nerf on loot after a hard wipe was added because people would deliberately wipe after a part in a quest where a ton of easy enemies would come rushing out. They would effectly just farm engrams like the treasure cave by repeating that part of the mission.