"The officer drove away but stopped and backed up, almost hitting the pair, Johnson said. He said he wasn't sure what prompted the officer to return. Johnson told MSNBC the officer said something to the effect of "What'd you say?"
What part of the enlarged area does say the officer started to drive away?
Is says THE OFFICER DROVE AWAY BUT STOPPED AND BACKED UP
That says there were four separate events:
Event 1-The jaywalking stop.
Event 2 - The officer starts driving away
Event 3- The officer stops and back up
Event 4 - The officer gets out of the car and shoots Brown.
As I've said many times, had the officer shot Brown during Event 1, it was all on Brown.
However, even your quote says that Event ended and others started. Once that first Event ends, it's not about the cop getting punched.