It looked like they had 4-6 SMN using Astral Flow though.
I REALLY like the idea of dual Chainstuns though. They macroed it so when there was 10 seconds left on Chainstun the next pair of RDMs went so they could cover lag/human delay.
It is sped up slightly but again, if you look at the icons on the RDM who is taking the video, Dynamis Lord died before his Chainspell wore which means it took less than 30 seconds to defeat him.