At c.33 minutes we see the ship's first aid cabinet on the wall of the captain's berth marked with a Red Cross symbol. In a Turkish ship the marking would be a Red Crescent (or, commonly, a Red Cross and a Red Crescent side by side) but never solely a Red Cross motif.
Near the end of the movie, Joseph Cotten is seen walking in the rain and entering a hotel. When he walks up to the front desk his suit looks hardly touched by the rain. However, in the next scene, when he enters his wife's room his suit is drenched.
During the chase outside the hotel in the rain, Banat's pistol, a P-08 "Luger" runs out of ammunition, but the action closes normally after he fires the last shot. This particular pistol was designed so that the action stays open after the last round is fired, giving a clear indication to the user that the gun is empty.