HP Requirement for Pink Bean

You're forgetting about his Big Bang attack (the 17k damage one). Cyanne said to "stay out of range" of it, but it's impossible to stay out of range of it when it has longer range than any ranged class. So the only way to not be in range is to have him facing the warriors.

I assume ranged classes have a max range of 400. PB's Big Bang has a max range of 500. I'm having serious doubts that the ranged classes can identify the attack fast enough and run away consistently for 2.1 billion HP worth of fighting, let alone do this while PB is literally being covered by flashy attack effects and hugeass numbers. (I'm thinking Rellik fights)