Wow, ok... you pop the defensive moves at the START of the fight because the Tank has no threat...how many times have you seen EOS pull threat at the start of a pull? The less damage the tank takes, the more threat they can build and the less heals that needs to be tossed out. You toss Bio second because its your hardest hitting dot, and you want it up asap, plus the 2.5 second buffer actually meshes the cool downs together with Bio 2 and Miasma. You cast it again because it will refresh the DOT to a near exact match with your Miasma 2 / Bio 2, so they're all on the same cool down. After that second fester, you cast 2 more ruin 1 then boom all your cool downs are at 3-4 seconds for a quick reapplication.