After all, in the palace where rumors are rife, even if she doesn't say anything, the incident in the Imperial Garden will sooner or later reach the Emperor's ears.
The most she'll miss out on is the credit for informing him first.
As the Empress, she cannot afford to make mistakes or it would endanger the crown prince. Hence she doesn't need the credit for informing the Emperor to secure her position; quite the opposite in fact.
The Empress did not expect that the first to inform the Emperor would be Concubine Shu.
That girl is Concubine Shu's own niece.
It makes sense.
Not being favored by Concubine Shu benefited her. Her invention of the bellows and glutinous rice mortar earned the Emperor's praise. However, not only did Concubine Shu not bask in her glory, she was even punished because of her. And today, the Fifth Prince was pushed into water by her.