The purpose of hiding the word "Lu Junyi's rebellion" and telling Lu Junyi that "it's safe to flee against the bow" is to let Lu Junyi go out and flee so that Liangshan heroes can catch him up the mountain, to provide evidence for Li Gu to sue "Lu Junyi's rebellion" and to tell Li Gu that "a righteous man carries a three-foot sword, but he must behead the rebel." In order to encourage Li Gu to frame Mr. Lu and remind Li Guruo that Lu Junyi is a "rebel", he can occupy his property fair and square, without having to rely on others.
Wu is yin enough. ...