In Bullitt, the bad guy shoots a cop in the airport with a 1911, then Bullitt shoots him twice with a Colt Diamondback. Both hit their target at least twice, kills them DRT. Or at least the cop falls down, but he WAS hit with a .45ACP, but that kills you and they might as well change the death certificate on your dead grandfather. Heart attack 24 years prior? No, he died of time travelling .45. That round is that good. Ask Colion Noir. I like that guy more and more the more I learn about him.
Anyway. McQueen is in civvies. He shoots the bad guy and he falls down. Everyone gawks at the dead bad guy. Not the shot cop. Not the gun wielding guy standing over him.
Hollywood? Almost certainly. But what would YOU do? I guess the guy in civvies gets a pass from us 'bystander' on instinct, having offed the guy that shot a cop. But I'd be a little wary of the dude with a gun that just shot another dude...
In the same vein as the fireworks launch failures. You walk out of a building. The street in front of you goes left to right in this city. To the left is some sort of commotion you can't make out. It could be Godzilla, it could be some homeless guy being sick in the road. People are moving away from the commotion to the left at a jogging pace. Not running, but faster than fast walking. A trot. What do you do?
Some people wanna check out the commotion, other automatically book it right because those people have been outside longer than you and might know something you don't.