Especially since ED is still being buffed by Raging Strikes. That rotation has you using your most powerful move twice, and your second most powerful (ED) once, all while under the effect of RS. Not to mention the extended DoTs.

If RS isn't up, then naturally you save that charge for another Fester since you're not trying to beat the timer and maximize the RS buff advantage. I did make a booboo though, the end has you use Ruin II before ED and not after, because you want to get that MP back also since Ruin II is so thirsty. I only use it over R1 because, as an instant, it doesn't lock you out from casting that last Fester like Ruin might if RS expired during the cast.