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     As serious as a heart attack.  Maybe those were Ken Kramer's last words, like a final explosion of panic in his mind as he stopped breathing and dropped into the abyss.  He was out of line, in every way there was, and he knew it.  He was where he shouldn't have been, with someone he shouldn't have been with, carrying something he should have kept in a safer place.  But he was getting away with it.  He was playing and winning.  He was on top of his game.  He was probably smiling.  Until the sudden thump deep inside his chest betrayed him.  Then everything turned around.  Success became instant catastrophe.  He had no time to put anything right.
-The Enemy, Lee Child