My read is that when the two pulled over, Mr. BMW confronted Mr. Prius and Mr. Prius went back into his car until LEO arrived. Then Mr. BMW got in his car, T-boned the Prius on the driver’s side, pushed it through the lot, and shot at Mr. Prius. Then Mr. Prius shot back at Mr. BMW, striking and mortally wounding Mr. BMW through the BMW’s windshield.
That’s how it read to me too.