William Saddler and the Highway Showdown

William saddler is chased by billy zane on a desert highway. They have a showdown slash shoot out, and there's this huge fiery ramming explosion. Saddler gets out of it at the last second,. So william saddler escapes the flaming wreckage. And then he just sort of ambles on through the night. He has places to be, an apocalypsis to prevent - but why would we actually believe that?