KANSAS CITY — It had been on their minds the whole time, but somewhat abstractly, one of those hardships that sports and adrenaline and well-trained, myopic focus have a way of alchemizing into something like motivation, or at least have a way of distracting from. Then Auburn entered its locker room after its 97–80 win over No. 1 seed North Carolina in Friday’s Sweet 16 and saw Chuma Okeke, their leading scorer in that game, at rest in front of his locker—the team’s first time seeing the sophomore forward since the 8:08 mark of the game, when Okeke was helped off the court after his left leg gave out as he drove to the hoop, sending him collapsing to the court.