In the event of an imminent nuclear apocalypse, we suspect that many people who have access to private jets will immediately take to the skies and escape city centers. This site tracks this indicator in realtime. The current emergency level is reported on a scale of 1 to 5, with 5 being an indicator of a likely imminent apocalypse.
I think the point is the system is so corrupt the 1% will get enough warning lead time to get out and get to their bunker, or at least be well clear of the EMP zones. I.e hours not seconds.