I'm not sure do healers really help at Rahab. I'd imagine you need at least two with high amounts of Atk- and/or Overdrive extensions. Even bringing multiple dispels by themselves probably won't do much. I'm not really one to talk, but since it either requires an absurd amount of tools or huge DPS to clear.

Thus, it feels like a DPS race more than anything, since anyone who hasn't put thousands of dollars into the game is unlikely to have the huge amount of tools required to keep Rahab under control.