No idea what I would've done honestly. Dude with the gun doesn't say shit about being a cop, but it's pretty clear from his fashion sense he is. Do we know of the cop came out of that black car? 'Cuz it looks like it was an unmarked car too. I can easily imagine being spooked enough that I might just accidentally drop the bike. Which, if you're a brown person, could easily turn into "he tried to run so I shot him."
It looks like no one stuck around to see what was going on. I can't believe someone can just stroll down the street with their handgun out & then walk up to & harass someone.