Revealing mistake: The British intelligence officer Wells, who is being trained to infiltrate the Gestapo headquarters at Lyon, would never pass as a German because of his slight but still quite noticable accent.
Revealing mistake: On their escape in the jeep from the Gestapo headquarters the two protagonists are shot at directly from the front. One bullet makes a hole in the windshield right in front of Sellinger's chest and should have hit him.
When Halloran sets the barn on fire to distract the Germans he lights up some straw with a match. All of a sudden you see flames flickering up at various places which could not be caused by the fire he made.