The “innocent bystander” could have been grazed by a bullet that went through the perp—or missed completely—and struck some part of his own car and ricocheted.
The perp wasn’t “blown back” by the wounding bullet, but instinctively tried to get away. The perp’s passenger looks perplexed, probably re-thinking his initial support for the perp.
“showering glass over another motorist whose window was smashed by a stray bullet”