When Wu Yong attacked Zengtou City in Water Margin, why did he stop Lu Junyi from being a pioneer?

Wu Yong is a die-hard fan of Song Jiang. Classics left his last words when he died. Whoever catches Shi Wengong is the owner of the cottage. Lu Junyi is known as the "Three Musts" in Hebei Province. On martial arts, Shi Wengong is a cinch. Wu Yong was selfish for a while because he was afraid that the owner of the cottage would not be owned by Sung River. It is also clear in the book:

The Water Margin Chapter 68 Song Gongming raided Lu Junyi, the first city, and captured Shi Wengong alive.

With Wu's idea, he was afraid that Lu Junyi would catch him, but he was afraid that Sung River could not stand the classical last words and made way for him, so he wouldn't promise. Sung river was careless. As long as Lu Junyi makes meritorious service, take this opportunity to teach him to be the master of the cottage and live up to the classic last words. Wu Yong refused, and immediately called Mr. Lu and Yan Qing to lead a 500-step army to listen to the bugle call on Pingchuan Road.

For reference only, I hope it will help you.