The winds of potato magic blow ever stronger. And so does the Sinnerman mission ("quest"?):
Attempt 1:
1. From the moment you meet Jablonski to the moment you meet Wacko-Jesus you are not allowed to save the game.
2. When you exit the car with Jablonski who rushes to kill Wacko-Jesus, if you run ahead of him, the cop will kill Jablonski as per the game script.
However, that is when the "police "system"" kicks in, the cop considers you a felon, you get a wanted rating, and the cop shoots you down.
It gets better - the cop seems to be invulnerable because he is a quest NPC
Reload game, try again.
Attempt 2:
1. Go through the car chase again because you are not allowed to save the game, complete with dumb ass scripted cars that jump in your way, to add "tension".
2. Once you start chasing Wacko-Jesus who is riding in the NCPD car, a quest-specific "car chase" music starts.
3. If you turn down Wacko-Jesus and refuse to ride with him, the mission ends there, which is really a deliverance.
However, the "car chase" music never stops.
I've seen people reporting this bug with combat music and one suggestion was to enter some other combat so the music switches and then stops after that combat is over, supposedly.
Didn't work. Reload game, fuck this mission, go do something else.
Potato magic at work.
PP: these bugs would be discovered by the most superficial of QA testing. You can bet your balls no one in CDPR played through this mission more than once, making sure he passes it right.