Yang Tianyi bought a bunch of missiles and other stuff to bomb the entire palace the next day if Chen Ming failed in his mission. He would first use the invisibility cloak he purchased to save the man and plant bombs all around the palace, solving his problem in a go.
But that would risk revealing his only secret in front of his Empress, which he didn't want to do.
Thus, in the morning, he woke up and when he found Chen Ming walking toward him from the direction of the palace, completely unharmed and with a smile on his face, Yang Tianyi released the breath he was holding as he raised his head and asked, "What's up? What happened?"
"There's good news, Your Majesty. We managed to assassinate the enemy Emperor last night. The entire palace must be in chaos right now!"