On an individual level, we all have a variety of hammers over our heads. Cancer has killed far more people prematurely than nuclear weapons. Something like 500,000 people a year are murdered. Traffic/bicycle/pedestrian accidents also kill more than nuclear weapons. Even compared to a once-in-a-century nuclear war that perhaps kills a billion people, cancer will kill roughly a billion in the next century anyway. So, for the rational/selfish person, the nuclear threat isn't worth worrying about.