The second half of the movie differs from the novel, with Austin dropped into a remote part of Saudi Arabia on a solo mission and ordered to rescue a prisoner from a group of extremists, a mission later revealed to be a test of Austin's abilities.
The movie's second half diverges from the book by placing Austin in a secluded part of Saudi Arabia for a solitary mission to rescue a captive held by extremist militants. This mission turns out to be a test designed to evaluate Austin's abilities.