The video was uploaded by "Patrick Ability" on Youtube, who I doubt is Synce. Synce just shared the video on FSD.
As for how Patrick got it: no clue. Maybe he's a dev, friend of a dev, friend of a friend of a dev, was given some footage for publicity others weren't, etc.
As for how Patrick got it: no clue. Maybe he's a dev, friend of a dev, friend of a friend of a dev, was given some footage for publicity others weren't, etc.