Alternative perspective: a disoriented snake was dumped out of a bucket and, upon seeing the looming human, proceeded to defend itself. Being just a step and a half away from the truck, when your firefighter turned to flee the snake also took the opportunity to retreat to the nearest cover - the undercarriage. Since they're going in the same direction, the snake felt further threatened and maybe took another swing or two along the way. The whole incident sounds hilarious but I still feel like 2 of the more notable coachwhip attributes(speed and defensiveness) have led to another misunderstanding. If your firefighter had just placed the bucket on the ground and turned to face the other direction, I wager that snake would have calmly slithered out and away.