Brooklyn
I stand with John Locke.
He had a line of retreat and got up and left at least once and then came back.
I'm curious to know if he shot his gun through his pocket or if he had it out out his pocket/holster ready to fire at the time of the actual gun shot.
As I said it depends on when you consider the event start. Since it appears his wife did not leave at that time... it would not seem there was a threat until later.
At the time he fired he had no line of retreat.
It will make an interesting case...