Ambrose is MI7's best agent, but is also one of the three founding members of Vortex, a secret organization of hired assassins. They are behind the death of President Chamboa in Mozambique five years before the start of the movie. This time they plan to assassinate the Chinese premier Xiang Ping. But Ambrose finds out that his fellow founding member Titus Fisher has spilled information to MI7. So Ambrose has a Vortex member dubbed as "The Killer Cleaner" kill Fisher. And later on his other founding member Artem Karlenko. He and Vortex have a secret weapon: a drug called timoxeline barbebuttenol. Which allows him to control a person for a while before that person dies. He plans to make MI7's head Pamela Thorton do the crime.
Throughout half of the movie he appears as a very respected agent of MI7 who English himself looks up to. Due to this he easily manipulates both his allies and enemies.
When English finds him in the secret MI7 base in Switzerland he accidentally drinks the drug meant for Thorton. So Ambrose decides to let him do the crime. English is however able to fight the drug and Ambrose is forced to flee in a cable-car. English catches up to the MI7 traitor and the two men engage in a brief, brutal fistfight where English takes several hits to the groin, yet none of them seem to be effective. English later kicks Simon in the groin and takes his pistol. But English falls from the cable-car, yet fortunately the snow breaks his fall. Ambrose tries to shoot him but misses, English grabs what he thinks is a bullet proof shield. But the gadget actually shoots a rocket at the cable-car, destroying it and killing Ambrose.
Simon was an extremely diabolical, masterminded and powerful individual, able to control Vortex with iron fist.