Prediction for the ending of the main event world title match: Cena has Kane pinned and Reigns has Orton pinned. But the referee only sees Cena make the cover (or he sees Cena make the cover first, only about half a second before Reigns covers Orton) and counts the pinfall to declare Cena the winner. When Reigns hears the referee counting, he mistakenly assumes he's counting the pinfall for him and thinks he's won the WWE World Heavyweight Championship, only to get up and see the referee raising Cena's arm in victory instead. A good little way of making both men look almost equally victorious while keeping the strap on Cena.
Either that, or just the standard "Reigns spears Orton through the barricade (thus leaving both men incapacitated) while Cena finishes off Kane in the ring."