Massive plotholes and weaknesses
SPOILERS
Not a bad film, I especially enjoyed the interrogation scene (showing that the best form of 'torture' is psychological/psychotropic, not physical).
However, some massive plotholes etc:
Why did the schoolmarm report on the nazi teacher, when she was one herself?
Why do the Nazis need a 'base'? They are supposed to be slowly working behind the scenes to re-nazify Germany and are in no hurry. They're not out to destroy the world like in a Bond film.
Why did Quiller wander into the base by himself? Why not call for backup first?
Once they had captured Quiller, why did they let him wander the streets of Berlin for hours and how did they know to have the streets lined with agents to follow him? Why not just keep him in a room? This, again, seemed to be a nod to the Bond film device of 'let them get ashore - then kill them' etc.
October says Quiller has 'until dawn' to make a decision; but it is broad daylight by the time he leaves his hotel so surely too late anyway?
How on earth did the nazis have the foresight to put a bomb in a car in a garage which Quiller didn't even know was there, just on the offchance he might find it?
Why did Quiller just grab the dynamite and start the car - even the most novice spy would realise it could be a dummy with a second device or have a trembler switch. And why did he risk being blown up in the garage when he could have just opened the doors, got to a safe distance and thrown the bomb back in?