Zhao Yao did not kill Song Dachuan, deciding to use him and make him his spy in Southern Wei. Keeping Song Dachuan alive served a greater purpose than killing him.
Of course, Song Dachuan would not readily agree to Zhao Yao's proposal, but he had no choice. Zhao Yao had fed him poison; if he refused to work for Zhao Yao, he would immediately bleed from his seven orifices and die.
Although Song Dachuan refused boldly at first, he was actually most afraid of death. Few people in this world are not afraid of dying. Besides, he wanted to trample Duan Jiangcheng underfoot, so how could he die? Moreover, Zhao Yao did not ask him to do anything dangerous, just to convey Southern Wei's news to him. Furthermore, if he did a good job, Prince Han would reward him lavishly. Thinking it over, he realized this was beneficial for him.
