Bonus Objective in Scarlet's Playhouse?
To be honest I haven’t see any of the bonus objectives in that regard. Funnily enough, the only area i didn’t manage to avoid mobs was the centaur one (and the one before the pot boil).
Everything else was cake.
But I don’t see any related achievements or rewards for it even if so.
Duty is heavier than death.
I can’t remember, but it may have specifically mentioned the Centaur “Spike” Arena in the description. Also, it was in yellow text instead of the normal orange. I can’t seem to locate any mention of it anywhere (or my search skills are sadly lacking).