Seeing the usually obedient Rat King behaving so stubbornly, Lu Qingshan let it have its way and didn't return it to the Spirit Beast Bag.
Being tempered under the pressure of the Dragon Breath was indeed a good thing for the Rat King; it was an excellent opportunity to strengthen its courage.
...
Before the trio laid a nearly vertical passageway leading downward.
"Beyond this passageway, we should truly be entering the interior of the Dragon Pool," Mo Yan said gravely, "There's no time to waste, I'll take the lead."
Mo Yan leaped decisively, transforming into an Escaping Light, and was the first to move downwards.
Lu Qingshan and Zang Xiaojian naturally did not lag behind, following close behind, the three of them plummeted downward like shooting stars, heading deeper into the Dragon Pool.
They could clearly feel that the further down they went, the more intense the pressure from the Dragon Breath became.