Exactly. It's literally just a "movie demonstration".
I'm baffled that Vadim can have the knowledge to pull this stuff out and "fix" it, yet somehow still think it was an actual cut mission named "Movie Demo". This is all just testing of camera angle placement, NPC placement and AI commands in the playable open world.
The fact Vadim needed 4 takes to get it to work tells us that the test was done with traffic turned off, or possibly done at such an early time that AI traffic wasn't fully implemented.