The front-mounted machine gun is a threat only as long as I am in front of the car. The damage to the front axle should make it harder for the car to make quick turns, especially on what is likely to be soft ground on the side of the lake. While not a problem to a light, fast mech, such terrain can be difficult for a car nose damage. It's tempting to move away, but even when winged the car still moves, and can redeploy the infantry.
I go for a quicker solution, and move forward and to the side, keeping my front armor towards the car, and wait until at point blank range before using the laser again, blasting once more at the damaged front of the car. I'm aware that this will probably mean getting fired at by the machine gun, but moving sideways relative to the car and keeping my best armor towards it should limit the damage. The idea is to move in an arc, making use of surprise and the limited maneuverability of the car, and move beside the car so that the lake and the car are between me and the last known position of the infantry. Once beside the car, possibly using the car as a shield, I slam the side of it, with intent of having the car end up in the lake. Preferably upside down.
Next actions depend on the success or lack thereof in the duel with the armored vehicle, and any reports from Tomtom vs. the Chevalier, the actions of the infantry, and any new forces becoming apparent. As default plan, I keep evading the infantry - not because it would be dangerous but because taking it out with a laser would be time consuming, especially as Tomtom has a flamethrower in his arsenal - and continue towards the other two mechs, making sure that Tomtom won't end up between me and the Chevalier. Having the Chevalier between me and Tomtom would be far better, but an angle is okay. Especially an angle above 90 degrees.