If you watch both views, I think the guy who ultimately stopped it is the one responsible for letting it run amok in the first place. From the aerial view it looks like he jumps out to grab something, and when he does one of those orange things falls and jams on the accelerator. Then he chases it all the way across the field and when it finally slows up after plowing down those people he catches up, then jumps in and stops it.
Working at golf courses for years it cracks me up because I know how easy it is to have a golf cart get loose haha. We had about a 4 year old kid hop in one at a tournament when his parent wasn't looking and hit the gas. Thing took off and knocked over a table and maybe one or two people. I've also lightly tossed something in a cart before and had it bounce funny and hit the pedal - it's an exciting couple of seconds when those things take off on their own!