Answer
The answer is "Wake in Fright," a 1971 Australian psychological thriller directed by Ted Kotcheff. In the film, Donald Pleasence portrays a deranged character named Doc Tydon, a bush doctor and kangaroo hunter who terrorizes a young schoolteacher who becomes stranded in the outback. Pleasence's performance is widely considered one of his finest and most unsettling, showcasing his ability to play complex and disturbing characters.