The dog was probably incredibly timid and easily spooked before it ran away. My guess is this was a very timid dog to begin with, and the owner didn't spend enough time socializing the dog to help with that problem. A lot of working dogs are prone to being timid like that, and this dog looks like some kind of shepherd mix.
That said, even though the dog approached in a very timid and submissive manner, it walked right up to the owner without hesitation. It took the dog a little while to fully grasp what was going on, but you could definitely see the dog loosening up in just a few seconds, and it was clearly quite happy at the end of the video.