Because Xue Fanxin wanted to bring Zhou Xiaotong along, she did not escape very quickly. Apart from the part where Little Meow led them to run, the rest relied on their legs.
Even if they kept running, their speed was still not fast enough. This was because Zhou Xiaotong's stamina was limited and he did not have much ability. Even if he was only walking, he had to rest after walking for a while.
He really couldn't walk anymore. What could you do?
She couldn't just leave him alone, right?
It was impossible for Xue Fanxin to ignore Zhou Xiaotong, so she could only try her best to bring him along. In the end, she simply carried him and used her lightness technique.
Although she would be a little tired if she did this, she would be able to escape much faster.