Hathaway says that the phrase "sailing close to the wind" refers to a vessel's seaworthiness. It actually means orienting the bow of the vessel at so shallow an angle to the oncoming wind as to risk not being able to make enough or any headway. The phrase has absolutely nothing to do with seaworthiness.
When Dr. Gansa is putting on his yellow safety strap, he puts it on the wrong way. Hardly an error an experienced bicyclist would make.
After the scene where Gansa and his wife drive away from the press waiting outside his house, Chief Superintendent Innocent refers to him as a psychologist. He is a psychiatrist; a very different profession. Lewis doesn't correct her.