So what changes if the result is just death
Half right plane zero. She is kept alive, but for worse outcome "to not be a human".
But technically in this manga, this means she gonna show up again, stronger next time.
There are some unexpected outcomes for the next event:
1. Little girl denies treatment, to die as a needle user instead of a weak monster like Souma.
2. Mei somehow changes her heart and interrupt the ritual.
In both posibilities, thier boss would just force them against their will anyway, since he's portrayed to view them as tools, not anything close to a human.