He failed to keep the "big picture" and was distracted with what was really a minor task. That is the leading cause of flying accidents. Complacency leads one to forget about the task at hand.
Eastern Airlines had three crew members focus on changing out a burned out light bulb and let their plane descend into the swamps of southern Florida. They stopped "flying the plane" to deal with what was really a small issue.
This trooper saw something he thought was a possible risk and forgot about the larger risk of riding his motorcycle defensively and safely. That put him at huge risk -and those around him.
Same with tractor accidents. No matter what happens, keep operating your tractor until its stopped and shut down. Then deal with the distraction.