On the initial XRay page, there are Page/Chapter/Book tabs. The Chapter tab lets you select references by chapter using a dropdown.
Once you tap on a person or term, it brings up a list of references for the entire book. If you touch the graph at the top, it will jump to a page with the beginning of the closest chapter. Then you can swipe up to page though the chapter.
Swiping left & right seems to back up to previous page. Pretty odd, I would expect one to go forward and the other back, but they both page back.