Don't pop Berserk until your GCD will be up as the oGCD animation is completing in order to get every hit out of it. A little bit of skill speed (no more than 30 necessary, for sure) can help as well, after that point, in case of some lag in queuing up GCDs over the duration. You can get in 8 moves, so if pop Berserk just before Butcher's or Storm, you can get in 2 more combos and a Fracture or IB/SC. Usually the Leeches or especially Esuna will cost the healer more in dps than it could possibly save me by removing the Pacification (they will almost never manage to remove more than 4 seconds of it, and usually no more than 2), so I just carry Flash for dungeons.