Actually, you can have four outs in an inning: if the catcher drops the ball on strike three and first base is open, the batter can run to first and try to beat the throw. The pitcher still gets credit for a strikeout even if the batter gets to first base safely. It’s a fluke play, but the outcome of one World Series hinged on such a play.
The odds on DVAX’s HCV vaccine being successful are probably about as long as the dropped-third-strike parlay :- )