Part 2/7:
As the human population dwindles, the U.S. government takes action by constructing 500,000 bunkers designed to shelter survivors during the crisis. A lottery system is employed to determine who get to take refuge; each bunker will provide a single occupant a chance at life until the flu subsides. Equipped for up to 70 years of isolation, the bunkers supply their inhabitants with recycled water, exercise programs, and sustenance provided in the form of a protein shake known as saplival. The artificial environment helps regulate the inhabitants' sleep patterns by simulating realistic weather conditions.