Hello hello ^^ (this will become an habit :3 )
Official Testlive EU2 - Pve-c
Once you reach the final room of the main dungeon =>
The usual way to end it is to kill the priestess and it unlock the two doors on the sides of the room (little opinion on the same time : it’s not really clear at all that there is two separate destinations and where they will teleport you, you can a lil difference in the landscape throught the tp but maybe a little “press E to tp at the entrance or the sentinel” will be great on each of them ^^
Anyway, the issue is if you pay a visit to the MASSIVE ( ^^ ) fish and walk against the water wall, the scenario reset same as the fish, the doors get both closed and you have to kill again the priestess to go out (and ofc wait her to respawn 
)
Give me a sign if you need more infos or if it’s not clear enough 