I thought about running over his head. Truck is about 4.5 ton. Also have a hammer on board. Both options were too confronting for my vagina, so I just kept driving.
This is why I come here. It never occurred to me that there are people who kill kangaroos to put them out of their misery (rightfully). But don't be so hard on yourself, these actions would have done more damage to your psyche long term anyway. He'll probably still live a long life and probably just need to use a CPAP machine to sleep.