If the equation is “one person risks a massive medical event and/or dies so X many people won’t be mildly, temporarily inconvenienced” how large of a number must X be in order to make this acceptable?

I love peanuts but I don’t love them more than I love not causing someone else a medical emergency. Considering how unlikely anyone is to starve to death in the absence of nuts for a few hours (there are other foods!) the risk-reward equation seems out of balance. Besides, how inconvenienced is everyone on the flight when the plane is forced to make an emergency landing because of a life threatening medical emergency or death of a passenger? If one passenger insists on munching nuts after being instructed not to, and we have to make an emergency landing because their allergic seat mate now may die, with whom are we most aggravated?