Math ftw. Playing 4, blackout normally only procs about 40% of the time. Of course, that's 40% "per cast," so if I drop VT+VE+SW:P+MF, it damn near stuns every single pull. For non-elites, it is rare that they ever get to me just from dropping VT+VE+flay due to the combination of blackout procs and the slow effect of flay.