USA/USSR nuclear war is an extremely rare event (to the point where it never actually happened; but any reasonable reading of history recognizes that it could have happened), that kills a large number of people. Lets estimate between 70 and 160 million immediate deaths in the US. [0]. This would be between 35 and 80% of the population. Lets round this estimate to a flat 100 million.
In 2013, there was about 100,000 firearm injuries (~34,000 of which were fatal. and 21,000 were suicide) [1]
These two number are not directly comparable, because of population growth, and my considering non-fatal gun injuries but only immediately fatal nuclear injuries. However, both of these facts serve to make gun violence look relatively worse than nuclear violence.
Even with these simplifications, our gun violence is equivalent to a nuclear war every 100 years. Readings of history may vary, but I doubt we could survive 100 years of cold war without starting a nuclear war.
For simplicity, lets ignore population growth and just focus on the absolute numbers (which will make shootings look even worse, because the total population has increased).
[0] http://historynewsnetwork.org/article/129966
[1] https://en.wikipedia.org/wiki/Gun_violence_in_the_United_Sta...
Um, none?
Nuclear drills don't really do anything anyway, if a nuke is coming you're going to be dead regardless of you hiding under your desk.
Ridiculous as it may seem, I remember some information in the late 1970's about 'what to do in the event of a nuclear attack' and 'underneath a table' was one of the places they advised as a good place to hide.
Kind of like the Israeli standard warning to get into a concrete stairwell if you hear a missile alarm and don't have a real bomb shelter available. In a direct hit you're dead anyway, but mild defensive measures can vastly reduce the lethal radius of an attack.
EDIT: Here's a vintage poster on the subject. Fairly factually correct, but awful for morale: https://i.redd.it/fw2xx579qw401.jpg