So I pretty much inhaled this book. I'd seen the film a few years prior (I tend to read the books after seeing popular films/shows). The line "Same rules apply" stood out in the film, but a lot more so in the book - and I couldn't wait to finish it to maybe find out what he meant. Alas! I got no explanation, maybe it was covered but too subtle for me? I looked around online and can't seem to find an answer. Can anyone shed any light? As an aside, the novel ending hit so much harder than the one in the film, holy crap!