If a person dies an unnatural death (lo-alenu)- what does the Gemara say about possible reasons?

The Gemara explains that death or the "key to life", is one of the keys that God does not "hand over to anyone" (Ta'anit 2a). In other words, only He decides who will live or not, and obviously why that person should live or not. In general, some of the factors involved are: is the person utilizing the life that he's been given? Is he beneficial to others and needed for the betterment of the community and Am Yisrael?. Will more time bring him to analyze his life and improve, or does he live like a robot or animal, who just lives by rote with very little hope of "taking himself by the hand" and improving (teshuva), and perhaps he is even on a "downslope". What are the physical, psychological, and spiritual needs of his family and community (may his death be too painful for his mother, spouse, children, neighbors, friends…; maybe they've already gone through difficult challenges, and this may be too much for them)? Does he "deserve" (= is it beneficial for him and those around him) a sudden death or a prolonged one (to prepare himself and his family, or part with his beloved ones…), etc.. In short, if it's hard to be a CEO of a large corporation, it's unbelievably that much more complicated to run the entire world or even one person's life (especially because we each have free-will)!!