http://www.youtube.com/watch?v=ev_iw5QQm_4&feature=related
This is for our group attempting this right now. Don't forget to flip youtube vid to high quality
comment ftw
"We did the achievement yesterday. some tips
Every player get a letter. A,B,C,D,E.
B,C,D,E do spell 3, (it doesn't pull the boss). A pulls and start with timestop, after timestop pressing 1. B instant pressing 1 also, so C,D,E have 10 stacks. After this, everyone is doing HIS rotation with 3,1 (for exemple cast 3 for three seconds, then instant 1, and directly cast 3 for three seconds again) ... dont look for the other groupmembers. It tooks 9 trys.
1min 49 seks, we had over 70% HP after Defeat."