A bug our team found and a quick fix if you encounter it!

Once you complete the mission, and go up the elevator after getting all the treasure, the elevator seems to take you straight back to the same room, and then crashes your client.

In some cases you won't be able to log back into your character once you force close - it will say you are logging in and will hang there. However, if you hit escape, you will be able to pick "return to haven", and this will get you back on the test server.

Hope this helps anyone else who encounters the bug. Enjoy!