Copper Citadel boss room cannot be left

As it stands, there is no way to leave the boss arena in the copper citadel. It would be nice to have a checkpoint in there that lights up after you kill Jamanra so you can go back and loot.

Wait. You go through killing enemies and boss then go back through the map a second time to loot?

How is this still a thing a year later?

Because it would require them to completely alter the whole map for the 0,001% of the players who for some stupid reason want to backtrack in an almost entirely linear area to pick up loot.
You might have noticed that the boss cuts the initial arena in half and completely crashes the dreadnought before going to phase 2...