Warning: There are spoilers ahead for Back in Action.Matt (Jamie Foxx) lies to Emily (Cameron Diaz) about the ICS Key for an important reason in . The ICS key is the movie's Macguffin, which has the ability to manipulate any electronic system. Matt and Emily's CIA jobs require them to locate the ICS Key before it is seemingly lost during a plane crash. The fate of Back in Action's ICS Key remains unresolved for fifteen years, during which Matt and Emily get married, have two children, and build a life that has nothing to do with espionage.

The new lives Matt and Emily have built for themselves are upended when a video of them at a nightclub is seen by their allies and enemies. While being pursued, and that he took it because he did not want it falling into the wrong hands. Matt hid the ICS Key in a surprising location, leading all of Back in Action's characters to race toward this location to acquire the Key.

Even though Matt loves and trusts Emily, he did not confide in her about keeping the ICS Key because he knew she would be worried about the danger of taking this action. that he and Emily could rely on if their covers were blown. He wanted to believe that the past would not come back to haunt him, Emily, or their children, but he needed to take steps to protect their family if this plan did not work out.

While Matt's thinking makes sense, at the same time, keeping the ICS Key left him and Emily still tethered to the lives that they left behind. The danger they face in Back in Action proves that Emily's concerns about the dangers of keeping the ICS Key were warranted. Fortunately, Matt concealing this information does not destroy his relationship with Emily, and they are able to retrieve the ICS Key and help save the day during Back in Action's ending.

Matt hid the ICS Key at the home of Emily's mother, Ginny (Glenn Close), in England. He explains that . Ginny was an unparalleled MI6 sniper and now runs her own military firm. As seen when Matt, Emily, and their children travel to England to retrieve the ICS Key, Ginny's estate is guarded by state-of-the-art security, making it an ideal location to hide the Key.

Given how easily Chuck (Kyle Chandler) and his mercenaries break through the security, Emily's mother's home is not as impenetrable as Matt believed it to be. The hiding place still works out, though, as it brings Ginny and her boyfriend, Nigel (Jamie Demetriou), into the fight, and both prove to be invaluable in stopping Chuck and preventing the ICS Key from unleashing global catastrophe. Hiding the ICS Key there in also allows Ginny to meet her grandchildren and for her and Emily to work through their longstanding issues with each other.