Dance Dance Retribution  

We used secondary burns on Anashti starting at 100%, while mezz'ing and offtanking the adds, and killing crystals when they spawned. We were able to get her to 75% when the adds stop spawning with only 2 waves of adds. At 75%, we gated out any bots or people who have repeatedly failed in the past, and cranked out full burns. She does mortal decay from 70-45%, and she starts emoting 30seconds from when she changes to damsel of decay. You have 2 ticks to get everyone in the raid into the aura in that time, making sure you have the buff in your song window. We were able to get her to 45% with only 1 emote and successfully complete the achievement. IF you happen to fail it on your first go, you must re-trigger the instance to succeed on the second attempt.