The coat worn by the Colonel is not closed. An officer would never do that. The style, the berets are worn by the Captain and the Colonel is rather of a soldier during Basic Training, not of an experienced soldier. 2nd Lieutenant Wemmer is portrayed as an officer, who studied during his service for the German Armed Forces. At least, he would have the rank of a 1st Lieutenant. The Military Engineers Facility, where the unit is stationed, would be not like an usual military base with marching soldiers all around, but rather a wide base with a lot of workshops, tanks and weapon systems to test them. Even would not everybody be a soldier at that facility, but also many civilian engineers, mechanics and employees.
Had the working title "Das gute Gewissen".