Bookmark your page before handing the Kindle over. For all the Kindle knows, it's *you* pushing all those buttons and skipping fast through a part you don't want to read.
Usually the "back" button will get you back to your page if they haven't done too much jumping around. The "back" button will step you back through the pages you've just visited. I'm not sure how far back you can go so bookmarking is the safest way to go.