I searched through the threads, and was unable to find one using this strategy. If this is a verifiable repost to a thread on these forums, I will delete the thread.
Want to know what Opera event you are up against? Here is what we do in our guild.
We clear all the trash up to Barnes. All but one person in the raid goes back and hugs the wall to the left located at the top of the ramp where you first encounter the Spectral Performers.
The one person staying behind talks to Barnes to begin the event but does not go on stage, but returns to the rest of the group.
The event starts, you can read what Barnes says, and about 30-45 seconds later, the event resets, unless its Oz. No damage to gear, no deaths, easy peasy.
I hope someone can use this to make there life in Kara easier.
DISCLAIMER: I take no responsibility to what happens if everyone is not hugging the wall when the event spawns.