[dragnet2]

To allow a situation, in which there was no need to escalate it to the level of a confrontation in the first place, to deteriorate to the point where he felt the need to use his firearm was, at the least, ill-advised.

For all you know, Zimmerman was simply following Martin so when the cops responded on scene, he could tell them where Martin was or was last seen. If Zimmerman was suddenly attacked by Martin, how would Zimmerman have known in advance this would occur simply because he was following someone?

[Jonty30]

If you do not know how dangerous the other person is or where may be, you extricate yourself from the situation immediately. You don’t wait to find out.