I woke up one afternoon (I was in college) to some loud noises coming from outside the apartment. I knew my roommate had already gone to work but I figured he was back for lunch or something, so I got up to, uh, ask him to keep it down.
Outside the apartment was a small completely privacy-fenced (6') yard with no gate. The only way in or out of the yard was through a sliding glass door in the living room.
So I walk into the living room in my underwear and I see a black male, maybe 5'10", 180lbs, holding a club (I later found out it was a shovel handle... the son of a bitch broke my shovel!) and trying to pry open the door with a screwdriver.
Not having a phone in the apartment, I ran back into my room, dove under the bed and grabbed my Walther P99, slammed a high cap into it, racked the slide and decocked it into double action. I yanked off my socks (didn't want to slip on the laminate floor) and ran into the hallway adjacent to the living room and peered around. He's still trying to get the door open, so I think:
A) Legal shoot? Yes -- he's in the curtilage of the house, in the process of committing a felony on it. He's armed.
B) Safe shoot? Probably not -- he's behind a safety glass door and directly behind him, maybe 40 feet distance, is a house that may be occupied. It's brick but I'm shooting 9mm +P.
C) Moral shoot? Probably not -- I can see both of his hands and he doesn't have a ranged weapon, just a screwdriver and a club. For the time being I'm safe behind the door.
So I hold the pistol behind my back and step out and challenge him, "What the hell are you doing?" He looks at my nearly naked, pasty self and shouts "Where Ricky at? That nigga owes me ten thousand dollars."
Ricky's my next door neighbor who lives on the other side of the duplex with his girlfriend and her (their?) two kids. I tell him I've never heard of any Ricky and that he needs to get the hell out of here. He looks completely unafraid of me, so I let the pistol fall to my side, at which point he runs away and jumps over the fence.
I never actually called the cops because my roommate didn't come back until 3 AM, and I didn't want to leave the apartment (at the time I was convinced he'd come back for the gun as soon as I left). I didn't have my contacts in so I couldn't describe the guy (plus, I was looking at his hands, not his face..), and I didn't want to get my neighbor in (more) trouble.
This is why I have no problem believing there are a lot more SDs than are reported every year.