Gu Sheng entered together with the people from the Thousand Poison Sect. He was well aware of the might of the Demon Suppression Golden Scroll and the Vajra Demon Suppression Bell—treasures of such caliber that exceeded the Dark Level. Naturally, Gu Sheng wasn't going to give up on them so easily. However, given the current strength of the barrier, it would take at least another half month for it to disappear. Gu Sheng wasn't willing to waste that time idly.
The reason he told Lin Miaomiao and the other two to retreat early was simple: once the barrier disappeared, a brutal power struggle was bound to ensue, with a large number of Golden Bone Realm combatants joining the fray. Given Lin Miaomiao and her companions' current strength, they wouldn't be of much use even if they stayed inside, and retreating early was safer.
Gu Sheng shook his head and said, "I will go, but now is not the time. For now, I have a favor to ask of you, senior brother and sisters."