Camus quest: stuck in the instance

So I started this quest with Camus; where I get moved to a different instance. The quest is 69, I am 79.

The first part was a trial by error: run around these giants and kill 20 of them. I realized that the can would kill them, but it won't count if you don't attack them first; so I ended up running around, attacking 3-4 at time, and then trigger a barrel.

The second part is more complex: you ahve to pick a column, then some enemies start to spawn and you have to last for 1 minute, and then kill all the enemies; but if you go out of the column range, the counter reset and you have to start all over. I was not able to pass this quest even if I am 10 level higher than the quest itself. Not sure if there is some sort of tricks, because I tried many times and I end up dying all the time.

Although,the big issue here is that I cannot get away from the instance. Even if I cancel the quest, it will appear again; I can't get out of the instance in any way, since the whole map of the sanctuary is empty, beside the area where the quest is supposed to happen; basically I am stuck without a way to get out.

How do you actually get out of that instance?

It's what some call the specialization quest (make you upgrade your class. Cygnus -> Aquarius in your case) and gain a skill.

You should be able to escape it with the teleportation scroll (Second tab and then second page of the skills list)

Btw at level 79 it should be easy to do this.