He is credited with preventing a nuclear holocaust during the Cold War. He was the duty officer monitoring a Soviet early warning system from a bunker near Moscow In September, 1983, when the radar screen suddenly appeared to show a missile inbound from the United States. He ordered his subordinates not to panic, while the alert siren blared. A message on the main screen reported that four more missiles had been launched. He had 15 minutes to determine whether the threat was real and report to his commanders. He believed that a real U.S. attack would involve several more missiles to limit the chance of Soviet retaliation. He convinced his Kremlin superiors not to shoot back, thinking that the alert must have been caused by a malfunction. He was right.