Dark alley. Possible violent crime in progress. Rookie passenger cop has his weapon out.
Loud noise, human figure pops up in driver’s window. If the driver was startled, he might have made a noise, too.
Poorly-trained rookie officer misinterprets everything and reacts badly.
Bang.
I could see it happening that way.
He had two years on the force, the driver had one. Neither was a rookie.
I don’t think he was exactly a rookie as he already served 2 years but he was a affirmative action cob, for the reason that he was a Somali refugee.