There is no evidence to confirm that premise.
You seem to be saying that keeping a suspicious person in sight equals initiating a confrontation.
That's a pretty far-fetched conclusion.
There is evidence that Z's NW training advices not to approach the suspicious person.
There is evidence from a previous call of Z's(9:27) to the police reporting a suspicious person
where Zimmerman says...”I don’t want to approach him personally”
...it shows in that instance Z wasn’t acting like some wild vigilante. He was doing what NW is suppose to do, watch and report. It is a data point at odds with the claims of some that he was a predatory hunter stalking M with the intent of confronting/executing/assassinating him.
That's an interesting find. I have been saying for a while that it is difficult for me to square the image of the "nervous Nelly" who calls the cops about open garage doors with the "vigilante" who wants to take the law into his own hands. I recognize that there is room for middle ground, but it seems to me he really can't be both. This recording certainly suggests that a confrontation with Martin is not something Zimmerman was likely to have desired.