The living conditions inside The Hold, when one considers that the Predators, for generations, have been forced to subsist off one another in a desolate land of darkness for generations. Is it any wonder they want to escape?
And what if it's the exact opposite? If they don't need to eat each other...or breathe...or feel...it wouldn't be any surprise if they're royally pissed at the herbivores for this.
Arizona, one of the fighters, is a child. Not only are the adult fighters going to whale on her like any other opponent without mercy, but if she wins, she'll have to face the Devourer. Alone.
The fact that, unless something drastic happened to the world of Foenum that allowed the Predators and herbivores to live in peace, this will keep on happening: a new Key Keeper will be elected to seal away the beasts...but not to reform them, but simply to keep them at bay. And seeing as they're already able to slightly escape from their prison already, then one day they may return regardless...for good.
The horror behind the idea that the characters are fighting to maintain a status quo in which predator species are hugely deficient is a massive case of this for everyone who didn't fail ecology. Many prey species adapt to predation by birthing huge numbers of young, and now the inhabitants of Foenum have no predators and are experiencing the boosts in child survival and lifespan that come from civilized living. This world will likely soon face mass overcrowding, resources shortages and constant plagues.
Try explaining to that to the race of sentient prey. They might adopt different tactics.