A qualified hunter might spend a few months in chasing his prey after crossing mountains and rivers for thousands of miles. However, it was just the blink of an eye's time for him to trigger his weapon to kill his prey...
Xia Yangming and Shi Zhongyu could never imagine that they had been under Zhang Tie's gaze since they escaped by Earth-River Vehicle; especially after they came out of the underground. Zhang Tie kept a close eye on them within 100,000 m.
In this process, Zhang Tie had a few opportunities to launch a strike; however, he didn't.
At the border of Dragon Emperor Big Domain, Zhang Tie had an opportunity to launch a strike. However, as it was not far from Dragon Emperor Big Domain, if he started a battle there, the two people might continue to escape by Earth-River Vehicle. Therefore, Zhang Tie didn't do it...