But Cao Cao said so, and he really wanted to leave Xuchang, so Liu Bei didn't dare to disobey Cao Cao's request. After all, even if Zhao Fei was by his side, he would lack a lot of opportunities to escape, but if he stayed in Xuchang City, he would have no chance at all.

As for Zhao Fei, Cao Cao asked himself to crusade against Yuan Shu with Liu Bei, one was to monitor Liu Bei, and the other was to let Liu Bei go. He couldn't let it go blatantly, so he asked Liu Bei to crusade against Yuan Shu, so that Liu Bei would have a chance to escape.