Level 7
Mordecai Roshwald
 During his forced residence, X-127 is ordered to push the bomb buttons to begin World War&nbsp;III (which lasts a total of 2 hours and 58 minutes). From that point, all civilian life moves from the surface of the earth to a collection of underground shelter complexes on the Levels 1 - 5, while military personnel already occupy Levels 6 and&nbsp;7. It later emerges that the orders given have been wholly automatic, and the war has taken place as a series of electronic responses to an initial accident. Toward the end of the novel, the inhabitants of the surviving shelters gradually find their deaths, as the surface contamination makes its way down past air filters and into ground water sources. At last, the inhabitants of "Level&nbsp;7" are exterminated through a malfunction in their nuclear power pile.