I'm just not convinced OP shot RS on purpose. What the Prosecutor is trying to drag out in minutia explanation only took probably less than 5-20 seconds. OP is on his stumps, jumping out of bed in a waking stupor, grabs his gun. Shoots.... pow! pow! pow! pow! The rest and in a state of shock, OP quite possibly does not remember except as it came back in flashes of memory. The Prosecutor is asking for specific details of time. OP accepts responsibility for what he did. It's the degree he must be held accountable which is in question.
Now, this is the main reason I refuse to have a gun in my house. That and I'd most likely use it on myself when I'm in one of those deep black funks to which I'm prone.