Paul fails the test given to him by the Bene Gesserit, and is killed by the Gom Jabbar. Unfortunately for Duncan Idaho, he doesn't stay dead for long.
Duncan wonders which of them is worse at hiding their feelings: Paul, who leaps into Duncan's arms when they reunite in front of the military men, or Duncan himself, clutching onto Paul and grinning like he's gone drunk on Caladanian wine.