The horses change direction during the race. When the race starts the horses are running clockwise around the track. But they finish the race running counter clockwise. And during the race the direction they're running switches back and forth. And it's not camera angles. Watching the background shows that we are seeing clips from races run in different directions.
Moriarty and Moran look to their right as the car taking Holmes and Watson to the train station leaves Baskerville Hall, yet the car is traveling to the left of their position.