How does the author use foreshadowing in The Illearth War?

In Chapter 20, Covenant is seen by Mhoram. The noticeable person missing with Covenant is Elena. There is a mention of a blast that rocks the ground and knocks Covenant off his feet. This is a moment of foreshadowing for the reader. It is at this point that the point of view switches from Troy to Covenant, and the tale of his journey with Elena to find the Seventh Ward is revealed.