Now that the masks had been ripped off, Suo Lun's crime of planning a rebellion could no longer be framed on anyone else, so he had no choice but to bury his head and pretend ignorance, and go directly to annihilate Tianshui City.
This course of action, without a doubt, was a tremendous destruction to Zhi Li's prestige and the kingdom's institutions.
How would all the lords and nobles under the heavens view him, Zhi Li?
By doing so, even if Zhi Li obliterated Suo Lun and ascended to the throne, the lords and nobles underneath would still disdain him in secret. And Duke Turing Tuo, without checks and balances, would become a powerful minister who could not be shaken off.
It could be said that launching an attack on Tianshui City without a just cause was a huge overextension of Zhi Li's future prospects, planting a massive hidden danger for his reign as king.
Knowing all these disadvantages and still proceeding, because Zhi Li knew he had no choice but to eliminate Suo Lun.