The Great Gatsby-chpt. 7+8

These chapters are the climax of the novel. Explain how something mentioned earlier might have hinted at this happening.
For me it was when Tom and Gatsby decided to switch cars, it was like a little red flag going up and saying um yea something big is obviously going to happen. My first guess/thought was that there was going to be some sort of mix up involving Gatsby's yellow car, which is true becuase Tom told Wilson that he owned the car. Also, when they were driving back home, Daisy and Gatsby were driving the yellow car (Daisy was the one Driving), but Myrtle had seen Tom driving the car earlier so she thought it was him, so she runs out to get his attention and talk to him, Daisy who is really the one in the car panics and plows Myrtle over. So, really in conclusion the fact that they switched cars brought about a big turn of events determining the end of the book.