An LA cab driver struggles to survive as he is forced to chauffeur a ruthless hit man to complete a series of jobs.

My version:

A taxi driver struggles to foil a professional contract killer’s plan to kill five people in one night after being forced to transport him around L.A.
(26 words)

Because merely surviving is not strong enough of an objective goal. ?When other people’ s lives are at stake in a plot, the protagonist must??struggle to not merely save his life but also to save the lives of innocent others. ? No exceptions — that is, ?if the protagonist is to emerge with not only his life but his dignity and ?win the emotional support of the audience.

And in “Collateral”, ?the taxi driver’s character arc is to go being a risk-aversive wimp to a risk-taking hero. And the standard job definition of a hero is some one who puts his life ?on the line for the sake of someone else.