Stuck inside rustbowl boss fight arena

Bug Report ID: #173152774

Can't exit the arena without hitting character select and then entering the boss fight again.

Defeated the boss, the invisible walls are still up with the "arena" entrances still present (for the situation where you might be stuck outside and want to get in). However, since the boss is defeated, I'd like to get out again.

For what it's worth: entered the arena with delerium, wore off mid way through the boss fight.

(as an aside, the design of vaal foundry has the same problem, you can get into the boss arena, but not back out to clear the rest of the map when it's done)