When King You entered the capital and his heir, Yin Huaixi, "died", most of the guards in the residence followed their masters to the battlefield. Only a mere 2,000 people were left in the You Residence.
Just as the two thousand people were fearless and fighting the Marquis of Changxing's men, Consort You ordered her servants to splash oil all over the residence and light fires everywhere.
By the time Marquis of Changxing and the others reacted, the fire had already covered the entire residence.
Only then did they know fear.
Originally, they wanted to accuse King You of treason and plotting a rebellion. In this way, it would make sense for them to barge into the King's Residence today, and the emperor would not blame them.
However, the fire prevented King You's Residence from being "searched". There was still no seal of the King You's Residence, so there was no way to naturally pin the crime on it.