Underrated Lang that has one of the best scenes in his filmography. When the brother taunts his sister for not being able to shoot her, the way it's shot in the darkness which is an element that was prior in the film associated with the subconscious gives his line a psychological undertone that reflects the state of the sister. In short, right here, we have another reason why Lang is the master of shadows and sound.
The intensity of blackness behind Carla, as she steps into the lit hallway has such a density to it's intension, that Lang and Sharp solidify a visual cue about the uncertainties behind one's intuitions in war-time darkness. The 'enemy' is not necessarily always a political view point standing across some clear line, but a cavernous fear that there's no real clarity until after a choice has been [wrongly] made.
A solid Fritz Lang thriller that had nice cinematography, a nightmarish story that has one event leading to the other, and Milland giving an effective performance of suave neuroticism. The only fault I found was that there were certain scenes where the film lost of its steam.
Not the best noir, nowhere near the best Lang. Much of the "suspense" is very easy to see through, unfortunately. Some characters seem to just disappear from the film without finishing their arcs. The 'epilogue' is absurd Hollywood rubbish. By no means a poor film, but certainly not an exceptional one.