You can activate Burning Rush right before entering the whack-a-gnoll arena and it won't fade away as long as you have the health for it, which means you're moving at 150% speed for the entire duration, making it easier to hit gnolls.
Of course, peccing Grimoire of Sacrifice for the extra healing helps you maintain it.
Of course, peccing Grimoire of Sacrifice for the extra healing helps you maintain it.