What is the author's style in Among the Enemy by Margaret Peterson Haddix?

The story is written in an easy-to-read format with action that flows quickly. There are several chapters of the book that end with foreshadowing intended to build suspense. One of these is seen at the end of Chapter Five. Percy is scouting ahead and Matthias hears a gunshot. He knows there's trouble but doesn't know until later that Percy has been shot. Another example of this is seen in chapter which ends when Matthias sees a man in a tree.