World Killer

S4 E5: Landing in San Francisco, the Sliders are amazed to find the city in ruins; not due to a Kromagg attack, but to complete abandonment. They discover that everyone has disappeared. When the Sliders head to Quinn's home, they find it empty like everywhere else. The difference: apparently the Quinn of this world built a machine that, when he threw the switch, wiped out every human being on Earth.