What happened that night was that Cliff and Kirk had what I think they described as a friendly argument about which of them was going to sleep in a particular bunk on the bus that night.
They decided to settle the matter by drawing cards. Cliff drew first, and he drew the Ace of Spades. They was no need for Kirk to draw, Cliff got the bunk.
Later on that night, the bus left the road, and everyone lived except Cliff, who was sleeping in the bunk he won with the Ace of Spades.
I read that when they got in the accident, which was apparently precipitated by black ice, Cliff was thrown out of the bus and then died when the bus subsequently fell on him.