In the movie Valkyrie (2008) Colonel Claus von Stauffenberg (Cruise) and his adjutant are returning to the air field after bombing Hitler's meeting. Adjutant Lieutenant Werner von Haeften throws the unused explosive and the cutter from the running vehicle, which catches the sight of the driver. Later on, this results in their apprehension for the bombing.
This mission was a very well-planned and designed one which was implemented by a number of high officials who would have been Hitler's inner circle. Even von Stauffenberg was one who was the most passionate and committed to this mission. Then, how could both of them do something which not only gave them away, but also gave away the fact that the SS was not staging a coup.
Why was it so mandatory to let go of those items before they boarded the flight? It's not like they were searched before they started from that air field.