For the sixth time in the last seven games, Gonzaga’s Andrew Nembhard never left the court. The senior point guard was outstanding in nearly every one of those games, but he exited the floor Thursday with his head and eyes down after a 74-68 upset loss to Arkansas in the Sweet 16. Nembhard, who has choreographed one of the nation’s top offenses, was held in check for one of the rare times this season.