
Ah yeah, the monsters are living longer in hard mode and the boss is still attacking the tank even though he remains near the wall. So the best tactic may be in trying to heal the 30k damage from the debuff and only run back to the wall when the monsters are going to come.
Our conentration was nearly gone that evening (it was 11:30 pm!) so that's why we decided to stop and went to sleep. So until now we didn't finish the raid in hard mode :(