Xingnan Base has been occupied by Su Sigui. As the one who controlled the base, it was certain that he wouldn't survive under Su Sigui's control. This situation bore a striking resemblance to Li Henian taking over Qinshan Base and the predicament Li Songhua found himself in.
Apart from this situation, the man surnamed Yang had another path, which matched Li Songhua's plan to escape from the base when the zombie horde attacked. He could seek help from a different force, hand over Xingnan Base, and then become a dependent of that force.
Yet, this option was far from desirable for the man surnamed Yang unless his situation was absolutely hopeless, just like Li Songhua.
Yet, the realization of this hope also required Li Songhua to overcome a difficult obstacle. The Li Henian in front of him and the zombies outside gathering for a revolt posed a formidable challenge, causing both men to fall silent for a moment.