When Reinhard Heydrich leaves Berlin to take up a new posting as Nazi Governor of Bohemia and Moravia (Czechoslovakia), a scene follows where Helmut Hoffmann is told "You'd better hope Himmler has a job for you, or you'll find yourself fighting Russians." This is in reference to the practice of the SS where General-SS members, without active assignments, would transfer to the Waffen-SS as military reservists. Interestingly, in the subsequent scene set a year later after Heydrich's assassination, Helmut is shown wearing a Waffen-SS tunic complete with combat and service awards from the Eastern Front, thus implying that he *did* find himself fighting Russians.
Commentators and critics of the film have often remarked that it is unclear exactly what Helmutt Hoffman's job is in the SS, apart from delivering things to his superiors for signature, and in only one instance is anyone actually seen working for him. Based on the dialogue, however, Hoffmann appears to be part of the SD Special Purpose Staff which was known as "Amt z.b.V. Besonderen Verwendung"
In the fall of 1932, when the film depicts the first meeting between Helmut Hoffmann and Reinhard Heydrich, Heydrich was an SS-Standartenführer (Colonel) and had served in the SS for just over a year. Considered rather unimportant by SS leaders, Heydrich would not become well known in the SS until after moving to Berlin and taking over the Gestapo in April of 1934.
At one point later in the movie you can hear a broadcast about the failed assassination attempt on Hitler. It is assumed that they are talking about Operation Valkyrie. Bill Nighy stared in both movies.