The ambulance crashes at a railroad crossing. After saving the two unconscious ambulance attendants from an oncoming train, Walt escapes. Then, using his chemistry expertise and a set of college medical textbooks, he develops a cure for cancer.
Changing his name to "Whitey Walters," he makes his new cancer cure public and becomes a beloved international hero. He then develops a cure for cerebral palsy.
Unfortunately, while on his way to give the good news to Flynn (who, impressed by his father's earlier cancer cure, now calls himself "Whitey, Jr.") and Skyler, he is tragically and ironically killed by Skinny Pete in a random, meth-induced street robbery.