I can’t imagine that part would have been edited out of the recording, so I guess he must be saying that Zimmerman was back in his car after the call, then left the car again. But there was not a lot of time between the call and the fight - 2 1/2 minutes max - for a second encounter at the car to have occurred.
I don't think the call is edited at all. So, if BOTH Serino's story of two speaking encounters, and the call are to be squared, they can't be in the same timeframe. I see two possibilities IF there was a first conversation, and both of them have the first conversation happening before the recorded call.
1. Z watching TM, TM comes over and they talk, window rolled up. Z keeps watching, and calls dispatch. Z's account over the phone is honest - TM stares, approaches, stares more, hands in waistband, runs.
2. Z watching TM, TM comes over and they talk, window rolled up. TM runs away. Z pissed. Z calls dispatch and makes up the narrative.
I don't see time for the recorded call, THEN two separate spoken encounters, the first with Z back in his truck. The evidence diverges too far from that theory.