During a break in filming at Stowe School in Buckinghamshire (where Russell Crowe's character watches his son play rugby union), one of the extras asked Russell Crowe for some acting advice. After their conversation, Crowe remembered the student's serious interest in acting and sent him autographed posters and photos from his film, Gladiator (2000), and wrote a letter saying, "A journey of thousand miles begins with a single step." The extra, Henry Cavill, went on to pursue his acting career and ultimately landed the role of Superman in Man of Steel (2013), with Crowe playing his father.
Russell Crowe and Meg Ryan became romantically involved during filming. Ryan and her husband, Dennis Quaid, divorced the next year.
Will Gaffney, stand-in for David Morse, was killed in a freak accident when a truck on which he was riding suddenly turned and drove off a cliff while being filmed in Quito, Ecuador. The movie is dedicated to him.
Originally it was planned that all extras were to receive the normal pay used for American extras. But the Ecuadorian government, which could not afford to have their actors paid that well, demanded that the production pay Ecuadorian salaries.
Terry (Russell Crowe) mentions being in the Special Air Service Regiment in Australia, then leaving to join the British SAS because of a lack of action. Post-Vietnam in Australia, operational deployments were highly limited, and often soldiers went entire careers without being deployed on operations. The British armed forces had more involvement internationally. This has since changed for Australia since the late 1990s.
Kessler's Bible is used for two maps of the area. The main map is drawn over Luke 21-22, which talks about the return of the Son of Man (Thorne will come and save Peter Bowman). The second map has a passage marked out, Matthew 5, which discusses the wrongness of revenge and loving your neighbor.
During the scene at 1:40 into the movie when he says, "these guys are my Panama crew", you can see a piece of cardboard on the wall behind with "JUST CAUSE" written on it. Operation Just Cause was a U.S. invasion of Panama to capture Manuel Noriega, military leader and drug criminal - a storyline very similar to the movie's plot.
The Actor portraing "Downtown 2", member of Terry's rescue team, was actually a member of the Ecuadorian Special Forces. Similarly, the actor portraing "Downtown 3" was one of the security advisors on the production, hence his excellent handling of the FN Minimi LMG during the rescue operation.
Most shoots encounter difficulty of some sort but the filming of Proof of Life (2000) was beset with them. They suffered frequent hailstorms, mudslides destroyed the roads to locations, 23 members of the crew came down with a case of severe altitude sickness, two volcanic eruptions and, at one point, tear gas wafting onto the set from a nearby riot.
One of the names of the hostages on the white board in the London Office is "Idziak" - the director of photography for this film is Slawomir Idziak.
The school bus full of children shown in the kidnapping scene are students of Colegio Aleman (German High School), a private school located outside of Quito chartered by the German government.
The ball cap Peter is wearing when he is kidnapped is from Rice University in Houston, Texas.
Castle Rock wanted Taylor Hackford to shoot the film in Mexico instead of 14,000 feet above sea level in Ecuador. They changed their mind when Hackford pointed out that there were more murders per capita in Mexico than Ecuador.