What's the story of Liao Wei during Qin Shihuang's reign? Why did he escape from Qin?

Liao Wei was an outstanding strategist of Wei State. Later, he was reused by Qin Shihuang and stayed in Qin State, where his military ability was particularly strong. In the process of commanding the battle, he always worked out a very good strategic strategy, gave advice to Qin Shihuang, and provided a good help for Qin Shihuang to unify the six countries. He fled the state of Qin because he was particularly afraid of the dictatorship of Qin Shihuang and his life was threatened.