This guy was done for the day, or at least for this run, and probably just wanted to get home or back to the store and keep his delivery time down. There happened to be another plan for him that day!
I know we would all like to believe we would ALWAYS stop and help someone in need, however, doing so could put you at great risk. In today's world, scams, criminals, even lawsuits most likely DO keep people from helping. I hope someday that changes.