What makes the entire room on fire in Inferno Butcher?
Solution 1:
It's effectively a 'soft enrage' - if you're taking too long on the fight, progressively more of the floor will light up until eventually the entire room is one giant cascading field of burny death.
Every time you have to revive is damage time lost, so first aim to.. well, not die. (Vastly harder than it sounds, I know, but it's still the truth!) Stocking up on ways to deal damage even when you have to run (the Wizard's Hydra, for example) can help make the difference as well.