If that foolish salary-man really was all about logic he would've taken flight towards the USA after receiving the super prototype (which would surely allow him to cover the distance) and defected early. Like is there a single reason for him to fight in the war at that point? No and handing over the prototype to the US would've allowed him to peacefully retire early. It wouldn't even matter if the Reich wins in Europe (which it obviously wouldn't quite as easily without his intervention), because he would be more than far enough from all that jazz. He should also realize that the fantasy USA are a more powerful faction, so it's all quite pointless and illogical what he is doing. My worst gripe with the story.