Watch the video. Just beat him like you are supposed to. With good team coordination & communication (2 level 30's and 4 level 29's), good upgraded weapons (Ice Breaker, Vision of Confluence, Atheon's Epilogue, Corrective Measure, Gjallahorn, Pocket Infinity, etc), I think it can be done in less time consistently than the time people can waste trying to "knock atheon off", which was supposedly patched so you shouldn't be able to regardless.