I would really appreciate it if anyone was able to give me a solution to this problem. I have tried to finish this achievement to the point where I feel like making a complaint letter. This is so ridiculous and it got me so frustrated. I have tried everything I could find out on what could go wrong and what to avoid, or what to do to get this achievement .
I have done the following without getting the achievement done :
The fact that I have to fight Balthazar every time when I try to restart this part of the story and the long talk and slow progression of this instance, I feel like this achievement is one of the worst there are in GW2.
Please, I need someone to help me out with this.