1. Get a squad of 3 AI in a Rhino MGS.
2. Fly an AR-2 Darter, and fire a laser marker at any position.
3. Attept to order the gunner to target the laser marker, and fire.
4. Order the commander of the vehicle to disembark.
5. Enter the commander seat of the vehicle.
If the AI still does not fire, switch back and fourth between the AI gunner's seat and your commander seat, or try entering and exiting the vehicle.