NATHAN RUBIN DIED because he got brave. Not the sustained kind of thing that wins you a medal in a war, but the split-second kind of blurting outrage that gets you killed on the street. He left home early, as he always did, six days a week, fifty weeks a year. A cautious breakfast, appropriate to a short round man aiming to stay in shape through his forties. A long walk down the carpeted corridors of a lakeside house appropriate to a man who earned a thousand dollars on each of those three hundred days he worked. A thumb on the button of the garage-door opener and a twist of the wrist to start the silent engine of his expensive imported sedan. A CD into the player, a backward sweep into his gravel driveway, a dab on the brake, a snick of the selector, a nudge on the gas, and the last short drive of his life was under way. Six forty-nine in the morning, Monday. The only light on his route to work was green, which was the proximate cause of his death. It meant that as he pulled into his secluded slot behind his professional building the prelude ahead of Bach's B Minor Fugue still had thirty-eight seconds left to run. He sat and heard it out until the last organ blast echoed to silence, which meant that as he got out of his car the three men were near enough for him to interpret