I think it's important to consider what GZ's intentions were when he got out of his vehicle. You suggest he was chasing TM, but are you implying he was chasing him with the desire for a confrontation? Or was he chasing/following him to see where he went/maintain a visual? Where did GZ say TM was headed?
The instant before GZ gets out of his vehicle, GZ says "Shit, he's running", to which the dispatcher replies to GZ "He's running? Which way is he running?". It was that query that prompted GZ to get out of his vehicle. GZ does not put his car into gear, or open his door until the dispatcher asks of him this information. I think it's generally understood, or assumed, that TM was fleeing south, down the T, which would mean GZ, from the location he was in at that very moment, inside his vehicle, parked on the street (by the second curve, north to south, on Twin Trees Lane), GZ was no longer able to tell the dispatcher exactly where TM went.
What was GZ's response to the dispatcher's question about where "the suspect" was headed? - "Down towards the other entrance of the neighborhood" when the dispatcher asks him to clarify, GZ says: "The back entrance". What does this mean? It means that GZ believed the suspect was fleeing to exit the neighborhood, not to go hide in wait for GZ somewhere near the intersection of the T, or to run away and return for a confrontation (it appears one or the other happened). I think it also means that GZ never envisioned any sort of confrontation taking place.