Conversation so far:
What happened in 78 with Bruno Sammartino?
After his second reign ended, Bruno Sammartino leisurely toured the U.S. and the world.
What did Bruno Sammartino do in his later career?
On January 22, 1980, Bruno Sammartino's former student Larry Zbyszko turned on him at the World Wrestling Federation's Championship Wrestling show.

Question: How did he turn on him?
Self-contained rewrite: How did Zbyszko turn on Bruno Sammartino at the World Wrestling Federation's Championship Wrestling show?