It’s the 64th minute of a World Cup quarter final. The referee has just awarded Ireland a penalty try, bringing them back into contention—now trailing by just one point, 24-25, against New Zealand, who are a man down with their hooker in the sin bin. Ireland has used five of their eight permitted substitutions. Looking to their bench, Ireland makes their sixth substitution: Ronan Kelleher for Dan Sheehan, one top-class hooker replacing another. Two substitutions remain available. New Zealand converts a penalty to extend their lead to four points. As fatigue deepens, Ireland faces a critical decision with just two…