Think about it. Mark Bishop is having what may as well be the worst night of his life, only to find that he's actually been in Hell reliving his last moments on Earth. He then decides to hail a cab driven by Charon, and it's there that the movie just ends. It's entirely possible Mark was dreaming all this up to cope with his wife leaving him.
WMG / Paranoia (2011)
The movie is All Just a Dream.