The Dao of cause and effect is profoundly mysterious; even if two events are destined to occur, a change in their timings can greatly affect the future.
At the moment when Hong Yun yielded his seat, Zhunti Daoist and Hong Yun became interconnected by cause and effect.
If Hong Yun were to achieve sainthood first, no matter whether Zhunti Daoist becomes a saint in the future, he would owe a huge debt of cause and effect to Hong Yun.
But if Zhunti Daoist becomes a saint first, the cause and effect would be immediately reversed. How could Hong Yun, who has not yet become a saint, withstand the cause and effect of a saint?
That would undoubtedly be turning the Heavenly Gang upside down!