If... and it's a Big IF... if Roy knocks out Cormier, is Cain going to be in the right mindset just watching his best friend get KOd? 
He doesn't really seem like the type to get rattled.
Yes.You have to the good with the bad.
He will have his own problems to deal with that night. 
There should be at least one upset on the main card.
Be afraid.
Be very afraid.