Goofs

Gavin Muir is credited onscreen as "Capt. Strong", but he is called "Hunter" and "Captain Hunter". 'Matthew Boulton' is credited onscreen as "Capt. Hunter" but was not in the print. Gavin Muir is Captain Strong and given credit as such. Matthew Boulton is credited onscreen and in print as Captain Hunter. They are two different characters and actors.

Whilst the bombers are attacking the German submarines, they change from single engine and twin engine aircraft. Not only is this a continuity error, but single engine warplanes did not at the time have the range to attack German submarines in the Atlantic Ocean.

Dr Lewis (John Garfield) goes to see Mr Goodwin (Moroni Olsen) in his study. As the camera looks directly at Goodwin, he closes a stamp album and puts his hands one in front of the other on the album. A side shot shows him with his right arm resting on the album and left hand on the desk. A shot looking over his shoulder shows him with both hands on the album as the first shot.

In the hospital, when Jane first tells Michael that he is in danger in having her as a patient, they are much farther apart in the close-ups than the immediately subsequent long shot.

At least one of the bombers taking off from Halifax to destroy the German submarines has American markings. The U.S.A. was not at war with Germany during the time of the film's setting.

When the bombers are attacking the U-boats, one shot shows the interior of a bomb bay and the release of the weapons. Just before the brief shot ends, one straggling bomb is shown dropping down a bit but hangs up in the bomb bay.

When Dr. Lewis tries to go up the stairs to the third floor of the house, he is stopped by Eddie holding a gun. When he comes back down the stairs, a large, distinct, moving shadow of the boom microphone can be seen on the well-lit wall behind him. (The same shadow can be briefly seen when he ascends the stairs, too.)