Thanks to a clause in the contract, where Denzel Washington needs to greenlight a director, Espinosa wasn't fired due to artistic differences between him and the producers. Denzel said that he wanted Espinosa to direct and that's that, so the producers let Espinosa finish the movie.
In an early draft of the screenplay, Matt Weston's ability to catch up to Tobin Frost was explained thusly: during his time at the CIA's academy for new agents in training, "The Farm", Frost's file was assigned to Weston as his case study. Weston had memorized Frost's history and used this data to explain to the CIA leaders where Frost would go once he was on the run. The scenes where Weston tracks down Frost in the South African township were kept for the final draft, but altered so Weston used ad hoc research skills to locate his charge.