Before making his move, Wang Qi specifically shouted "Indeterminate Sword" for a reason.
Indeterminate Sword is not the Mysterious Uncertainty Cloud Sword.
The main point is that it lacks the process of Probability Cloudization and Sword Qi forming a cloud. Its core isn't the Observer Effect explanation, which is commonly known as the "Copenhagen Interpretation."
This is a swordsmanship he perfected through reincarnation. The core is DH—Decoherence History.
The state a system undergoes within the same time period is not unique.
The past is not unique, the future is not unique, only the "present" is unique—this is the explanation of wave function collapse! Because the "now" in which "observation" occurs is unique, it can only be in a unique location, thus forming a definite microscopic particle!
And the Indeterminate Sword is precisely that "now."
From infinite past, cleave one of the infinite futures with the "present sword"!