I wonder why one JP group got angry at me for not getting three stacks from Dread tower >.>. Don't they understand the vulnerability debuff the tower applies?

So it is right to just get two stacks? How do you stagger the stacks? At what time to you get your second stack? I was just wondering when I should run in to grab another stack from the tower.

Also, should DPS be doing mines? Majority of DPS on second coil turn three just ignore the mines and let people bounce into them >.>(my first experience in this coil, the second tank got one and I exploded another and got bounced into the third).