Final answer:
When in the middle of a crossing, you should never shift gears in a vehicle as it can be dangerous.
Step-by-step explanation:
When you are in the middle of a crossing, it is important to never shift gears in a vehicle. Shifting gears can cause a disruption in the vehicle's movement and can be dangerous for both you and other pedestrians or vehicles nearby. It is best to remain in the same gear until you have completed the crossing and are in a safe location.