Well, at least this is a more clear cut case this time with multiple physically present witnesses so that there's much less chance of this being spun for one side (the defense). As I said before in the Treyvon Martin case though, this incident shows the problem with these kind of laws. They actively fucking foster a trigger happy mindset among those with guns. The most paranoid people are the ones most likely to "take advantage" of these laws and feel justified in using them.
By the way, concerning Zimmerman (although I don't want to go too much off the rails here), his whole girlfriend threatening incident did a lot to solidify that he's fucking mentally unstable.