Given the limited amount of info in that video, I doubt I would have even stopped at all in that situation.
Midnight, only one around, no hazard lights, both lanes arbitrarily blocked by cones, consistently trying to step in front of car to stop it (IE:clear intent to detain), no uniform, no identification......nope, no way I'm stopping.
Even when the guy stops there's no "oh thank up for stopping my car broke down" and the response to "can I help you" is " yeah.......ummmm...."
Taking off was definitely the right decision.
besides, if buddy was broken down, he would have called someone. Cell phones are more common than socks these days.....everyone has one.
For sure something fishy was going on there.....