Well done film, but don't over-analyze. *Spoilers*
***SPOILERS***
I wouldn't put much thought into it because the writers certainly didn't. It was just as another poster said, merely a plot device--a plot device that is specifically designed to be purposely ambiguous to allow the viewer to have fun coming up with their own interpretation of why he rapes her again. Our knee-jerk response is that he was severely traumatized. Hold your horses on that one.
If they had allowed him to undergo therapy...the rest of the narrative takes a sharp turn and anything as shocking as that scene immediately would come across as just a cheap, exploitative ploy. Noticed how the doctor was conveniently never available? You think that was just poor writing? Keep reading.
The plan was just to let the kid simmer in his juices while wasting away his days in abject misery, and then the subsequent rape is supposed to be a by-product of his inability to deal with what happened --giving us, armchair psychologists that we are, an excuse to pat ourselves on the back at having released our inner Sigmund Freud.
It's somewhat clever, but mostly just convenient--a little too convenient. They made him rather withdrawn and monosyllabic to begin with...and then just tossed in a bit of trauma to force him off the deep end. This was obvious to me in the way they dealt with his best friend quizzing him about his encounter with his girlfriend at the beginning of the movie.
He was uncharacteristically coy with any details for a 16-year-old boy who'd never had sex, but clearly had an opportunity to do so. It looked to me that the writers purposely kept him a virgin merely as a plot contrivance to heighten the shock of what was to come soon after. If he's not a virgin during the pivotal moment...the scene loses quite a bit of its shock value.
Think about it--his first full-fledged sexual experience just happens to be a forced encounter with his sister. Oh...the horror!!
The scene with Daniel and his brother-in-law in the restroom should have been the final determination that everything was just a plot device. Let's recap:
He's forced to have sex with his sister, whom he then rapes, OUT OF NOWHERE, after walking around in a daze for a week or so, buys a knife while in his tux on the way to her wedding, follows his brother-in-law into a restroom to kill him--but chickens out, and then jerks off in a cocktail and hands it to him to drink.
SERIOUSLY?!
Please guys...do yourselves a favor and don't try to over-analyze this film. There's a reason they only gave you vague details about this supposedly "true story"--it was mostly just poetic license. The framework of actual events given a generous helping of filler ...a salacious fantasy brought to life.
Think back to one particular scene between Daniel and his friend. The friend says, for no apparent reason, what we have been thinking since the film started, "Your sister is hot!" THAT is your reason for everything that happened--the initial encounter and the rape that occurred later. Elegant exploitation disguised as a deeply-moving, psychological treatise on the aftermath of sexual trauma.
If you don't believe me, think back to the long wide-shot that took place outside of the location where they were held. It was so long, that it seemed as if they weren't going to show us the sordid display of the forced encounter, as our voyeuristic tendencies and curiosity would demand that we see.
It looked as if they were going to let us imagine for ourselves the horror of what was happening behind those walls, and just have them come out and get back into the car--but they didn't. Ohhhhhh no! They wanted us to join in and make us a party to the guilt that the characters must have felt--thereby giving them an easy out in not having to explain why Daniel behaved as he did later.
Our collective guilt would therefore allow us to excuse anything Daniel did as merely his way of processing his grief...and they ultimately got to exploit a ridiculously gorgeous actress with a salacious act, not once...but twice.
If they had been given a larger budget and about 30 additional minutes...we would have seen them do it yet again, and this time she would have liked it and been conflicted. That movie's been done already, though a bit differently.
Look for Against The Wind starring Antonio Banderas.
This movie was meant to titillate...and the clues are all there. It may not be as much fun, but sometimes...the simple answer is indeed the answer. Sex sells.
I wish to die in my sleep like my grandfather--not screaming in terror like his passengers