"'And now you know. I'd risk my life for yours. But that doesn't mean I love you'" (218).

"'Do you know why I wanted you to save me?"
"No."
"Isn't it obvious?"
"No, it isn't."
"Because I love you'" (218).

In watching the movie Atonement, I felt much more significance was given to the drowning incident that needed to be. I always believed Briony's reason, that she was concerned with having the world "just so" and was blinded by her childish belief that everyone is either "all good" or "all bad." Perhaps, as I mentioned before, that was only the reason covering up her real reason, jealousy. In addition, the synopsis on the back of the movie Atonement also gives much more significance to this scene:

"...When a young girl catches her sister in a passionate embrace with a childhood friend, her jealousy drives her to tell a lie that will irrevocably change the course of all their lives forever..." (Thelma Adams, US Weekly). 

In contrast, the synopsis on the back of the novel says:

"...But Briony's incomplete grasp of adult motives and her precocious imagination bring about a crime that will change all their lives, a crime whose repercussions Atonement follows through the chaos and carnage of World War II and into the close of the twentieth century" (Back Cover). 

Keeping in mind that McEwan contributed heavily to the production of the movie Atonement, as well as the fact that Briony wrote the first portion of the novel, it is very possible that this incident between Robbie and Briony has much more significance than I had originally attributed to it. This helps me to view the movie, and the novel, in a much different light. However, as this is a fictitious story, a "real" interpretation is simply impossible. The only one who could perhaps offer a concrete answer in the matter, Ian McEwan, believes instead in the plethora of meanings that his readers derive from the work, instead of one, simple, concrete explanation.