Mentos
The cart screeches to a halt outside the battle as Mentos pulls out his spyglass and has a quick survey of the battlefield, before turning the cart to point at the largest concentration of archers he can find.

"Narrassillus." he says, covering the cart in adamantine plating. Rummaging through the supplies, he finds a small iron pot and puts it on his head as a helmet, and spurs the cart to the completely irresponsible and likely highly dangerous maximum speed.

"For the glory of the Grey Academy!" he yells at the top of his lungs, holding the spyglass in the air triumphantly, as the 200lb cart goes barrelling into the archers who were too slow to get out of the way at 140 miles an hour.

((So... do you want to roll the 70d6 damage, or should I?))