Up to now, no one outside of official circles has known exactly what would happen if a rogue state launched a nuclear missile at the Pentagon. Second by second and minute by minute, these are the real-life protocols that choreograph the end of civilisation as we know it. Frantic calls over secure lines work to confirm the worst as armoured helicopters are scrambled to evacuate the chosen few to secure bunkers. One nuclear missile will provoke two dozen in return. Decisions over hundreds of millions of lives need to be made within six minutes, based on partial information, knowing that once launched, nothing is capable of halting the destruction.