Zimmerman, dear, did not kill for fun - he killed because he did not use his common sense and he had a gun - a weapon much more effective than a packet of skittles and an iced tea.
Dear, some have suggested that the prosecution should have argued that Martin was actually the person standing his ground. After all, he was the one being pursued.
Doesn't quite fit your guys scenarios but Zimmerman was following Mr. Martin. And that fact is hard to argue.
Following someone is a legal endeavor.