This is what ICBM crews will do after a missile launch
Imagine turning the key to start the end of the world with a co-worker you may or may not actually like. That's the job of U.S. Air Force Intercontinental Ballistic Missile Crews. There's a good chance that after they launch their missiles, an enemy nuke will be on its way (if it wasn't already). The rest of their life will basically last another full ten minutes.
And they know it.
Of course, the Air Force didn't tell them that. If all went as planned, once their missile was fired away the airmen didn't really have anything else to do. At least officially. They would have had just a few weeks worth of food and water to last them through the coming nuclear war. If they couldn't leave the contained, "protected" area, they would likely die from thirst or lack of air.
If that sounds terrible, remember that the alternative is dying a horrible death on the surface, either from a nuclear fireball or from radiation sickness following the likely nuclear retaliation to come, if it was indeed coming. These troops would have hoped the United States successfully fired off its first-strike capability that the Russians would have no answer for.
The reality was that the airmen who fired those missiles fully expected to be vaporized by an 800 kiloton nuclear blast sent from Russia with love. Their best estimate was a life span of roughly 10 to 30 minutes before the Soviet nukes hit them. Even in the middle of nowhere heartland of America, the USSR knew exactly where the American ICBM silos were and had a target painted on each one of them. The moment the U.S. launched, there was a good chance the Soviets would also have launched.
The airmen in the protected underground bunker would have been totally vaporized and buried in their workspace, now their concrete tomb. These ICBM sites were only buried some 40 feet underground, which is not enough to protect them from even the mildest of Soviet nuclear missiles.
If the Soviets nuked Ellsworth Air Force Base, S.D. in the 1960s, the largest yield would have been 2.3 Megatons, enough to obliterate the base along with the surrounding area and nearby Rapid City. A surface detonation would have left a sparkling crater that generations later would probably have made a fine national park in the post-apocalyptic United States.
Still, according to Air Force training, the crews had a couple weeks worth of food, water, air, and other supplies. Among those supplies were shovels, so that the surviving crews could dig their ways out of the wrecked tunnels and concrete bunkers to take their new roles in whatever the world looked like after a nuclear exchange. No one actually believed this. Air Force ICBM crews during the Cold War believed they were doomed and (hopefully) lived their lives to the fullest.