What should airline passengers do if a pilot acts bizarrely?

When a pilot on a United Airlines flight from Austin to San Francisco launched into a bizarre rant last week over the plane intercom, the 120 passengers in the cabin were put in the awkward position of looking after their own safety. The pilot, who rambled on about Donald Trump, Hillary Clinton and her own divorce, was ultimately replaced on the flight and United Airlines apologized to the passengers - but not until several passengers got up and demanded to be let off the plane.