Maybe Zimmerman was a "wanna-be cop." Maybe he didn't make the best decision, or was even "arrogant and over zealous." But none of that matters in answering the question of whether or not he is guilty of murder. The only things that matter are whether there is at least a reasonable doubt that he was reasonably in fear of death or serious bodily injury from Martin, and whether there is at least a reasonable doubt that he did not first assault Martin.