Chi Xue's side, along with the other forces in the God Realm and the many Rogue Cultivators, had great overall strength. Ling Tian and the others might not be their match in a head-on clash. In other words, if those two factions joined forces, they could drive Ling Tian and his people away from the Rune Cultivators' rune formation without much difficulty.
In fact, given Ling Tian's cautious nature, he would never risk a head-on clash even against Chi Xue's side alone or the other God Realm forces and Rogue Cultivators—let alone against the two factions allied together. So it was inevitable that they would be forced to retreat from the rune formation.
Everyone knew Ling Tian wanted to avoid casualties, and they also understood how powerful Chi Xue's two factions were. They knew those factions could drive them back without much trouble. A few quick-witted people had already realized what Si Kong Xuan was getting at, though plenty of others—Fairy Sword Ji and Tan Tai Chang Feng, for instance—didn't think it was a concern.
"So what if they drive us away from the rune formation? We can come right back once they leave. While we're locked in a stalemate, we can use our advantage in archery to kill some of them. A standoff like that won't do them any good," Tan Tai Chang Feng said dismissively.
"Exactly. Whether we're facing Chi Xue's side or the Technology Cultivators, we can fight while retreating, because we're faster and our archery is better," Fairy Sword Ji chimed in. "With those advantages, we can toy with them in the palm of our hands. Driving us away won't help them. We can kill some of them along the way, then come back and harass them when they turn around to attack the rune formation.