The sneak attack by the Tianshan Tonglao was indeed very sudden, yet not entirely unexpected.
Ye Weiming knew that Tianshan Tonglao's current strength was not fully restored, with approximately only 30 years of her 90 years of internal strength regained. With the progression of the plot and the resulting time leap, she might have improved more than when Fei Yu last assessed her, but at most, it was just over 60 years of strength.
At this level, Tianshan Tonglao was definitely not a match for Ye Weiming.
Thinking from her perspective, Ye Weiming quickly came up with a series of tactics focused on sneak attacks and sabotage, used to increase the tactical advantage for Tianshan Tonglao under such extremely unfavorable conditions.
Among all these strategies, using Yinchuan as a distraction to draw Ye Weiming's attention while hiding nearby to wait for an opportunity to attack was only less foolish than launching a direct assault without any cover. It ranks third!