Siege at the City!
As Liu Bei's appointed commander-in-chief for this campaign, Wang Yue had to keep an eye on the overall situation if he wanted to take Cao Zhen's fifty-thousand-man army with minimal losses. So he had also been watching the north bank of the Yellow River closely.
When he heard that Sima Yi was leading the troops across the river, Wang Yue decided that capturing Sima Yi would be far better than killing Cao Zhen.
After all, once the Sima family seized the empire, they would truly leave the Central Plains devastated. Unless Wang Yue killed Sima Yi and his sons, he would never be able to rest easy.
So Wang Yue had been calculating how to wipe out Sima Yi's forces. When he learned that Sima Yi had launched attacks by water at two points, he immediately ordered Guan Yu to cross the river downstream and head for Qinghe.
The encirclement of the Ambush from Ten Sides had already tightened considerably. Guan Yu's position was now far from the main force. He had originally been there to monitor the Wei army and prevent it from crossing downstream, but now Guan Yu himself was crossing the river.
Sima Yi had his own plans at this point. He knew that Cao Zhen's forces were dwindling, and Cao Zhen certainly wouldn't wait for him to make arrangements. With so many enemy troops surrounding him, even if Sima Yi's men managed to build the pontoon bridge, the Great Han army would surely attack them with everything it had.
By then, the Wei army would be unable to hold them off, and Cao Zhen would certainly die.
Cao Zhen's only way out was to have his soldiers fight a path through the enemy and escort him to Hulao Pass, where he could