Or pick a champion who cannot be killed in the traditional sense. Seems like Dalinar et al seem to think they need to pick a human to fight another human. No reason the champion has to be a human or even a being from Roshar. Or heck, pick a champion from a completely different solar system. It would make the contest be virtually impossible to occur which might nullify it, thereby releasing Tod.
Fortunately we only have 2-3 years to wait to find out!.... *sad face*