I did try opening that one also but all the doors are locked. I even backtracked to the beginning and the door there is locked....I think i'm going to have to restart...
Well maybe the bug on trial 3 with kreia affected this because for some reason i need to talk to her THREE times to make me pass the test (same dialogue everything). The first 2 times i decided to stand with her and after the game didn't progress so the third time i just decided to let them kill each other. At this point they all turned on me and after finishing them easily i was allowed to pass.