 In summer 622, after Li Shimin defeated Liu, temporarily forcing Liu to flee to Eastern Tujue, Xu panicked and was not sure what to do.Under the suggestion of his subordinate Liu Fuli (劉復禮), he initially considered welcoming fellow rebel leader Liu Shiche (劉世徹), who had an honored reputation, to be his leader, but once LIu Shiche arrived, Xu, reminded that Zhai Rang had initially supported Li Mi but was ultimately killed by Li Mi, refused to support Liu Shiche and made him a general instead.Later on, suspicious of Liu Shiche, he had Liu Shiche executed.