Describe symbolism in The Last Lecture by Randy Pausch

Randy and Jai had a beautiful wedding in Pittsburgh. After the wedding they drifted off in a huge multicolored hot air balloon. Unfortunately, they hit a tree well going up, and things went out of control as the wind shifted, and they couldn't find a place to land. The couple was headed right towards a train track that had a train coming at them. They were told to run as soon as they hit the ground. They made it out safely, but it wasn't very romantic. This event was symbolic in that they had a rough start to their marriage, and in turn, they would have a rough ending to their lives together.