It is impossible to end the mission. Run the mission twice level 90-115 to get all three achievements. There are always mobs missing. The script seems to not count certain kills. I have to check that but I assume it is the big damage shield or the riposte of the level 115 which are not counted. So maximizing the damage to get the achievement for maximum damage breaks the script somehow.
If it is, it's not the script but the no-damage code. You have to do at least 1 point of damage not including passive sources, which DS is one, in order for the kill to count. It's just the way the code works and you have to account for it. Are you trying to pull and ripo the whole zone at once? Then don't run it that way. Find a balance of pulling where you can be sure that you are always landing a hit before it dies, or drop all DS buffs and hit an AE before anything suicides.
Third time: success. Did it without DS. But honestly? This cannot be intended. As a level 115 to get the conquest achievement is easy - as a level 85-90 this is highly doubtful as long as there are no ubah trying that. Lucky low levels that we had three high level in the group.
