I was doing a2 hell clear today with a group and found a treasure hunter NPC who had a timed dungeon. You go in and have ~2 minutes to find the treasure within. Our group was not able to do it in time, and some of us released finding out that we could no longer enter the dungeon.
1 party member did not release their corpse and we were able to portal in to them inside the dungeon repeatedly, and continued clearing to get the treasure.
edit: portal in means take their banner from the main town..