After six episodes, just in time for sweeps, we return to the "dad in a box" reveal from the superb "The Man From Tallahassee". It makes sense for the narrative as the events in this episode serve as major stepping stones for Locke and Sawyer, which will propel them through the end of the season. Anthony Cooper being the real Sawyer, a theory that's been kicked around since his introduction in "Deus Ex Machina", was hardly shocking. Since they went that way, the payoff would have to be worth it. Thankfully, it is, and has some great performances, including some of Josh Holloway's best work. This episode has some of the darkest material so far, with revenge and its complicity painted in its ugly extreme, negating any redemption we've seen so far.
One thing of note: previews for previous episodes featured some moments from this one (particularly The Others gathering around the night Ben tried to get Locke to kill his father for the ads for "D.O.C."). Were some of these scenes meant to be spread out from episodes 13 to 18? It makes sense for them to scrap that idea and throw them all in this episode, which makes the overall package more effective than if they did another flashback story.
This episode could've easily been changed to a Sawyer episode without much alteration. A likely flashback scenario would've been about the effect Cooper had on Sawyer immediately after his parents' death, and how he became a con man. However, such pieces of evidence have been described before in previous Sawyer episodes, and considering some of the flack "Lost" has received for redundant flashbacks, it may have been better to focus on what happened to Locke when he went with The Others.
Sawyer was heading towards redemption. He stepped up as a leader in Jack's absence and started a relationship, albeit one on a faulty foundation, with Kate. Now he has exacted revenge against the man he blamed for ruining his life and the aftermath has left him shattered. Some figured that Sawyer would confront the real Sawyer (who had to be on the island somehow) at the end of the arc. Perhaps a fitting way for him to redeem himself would be to spare him. However, with Sawyer fulfilling the vendetta he's had since he was a child, where does his character have to go from here?
Recalling "Outlaws", one problem haunting Sawyer was his quest for revenge lead him to kill an innocent man who owed one of Sawyer's ex-associates money. The common interpretation is the boar in the episode was the island's manifestation of his prior incident, and sparing the animal was a sign of him heading towards the right path. Exacting his revenge in brutal fashion is a major step back, one that will likely take the end of the series to make up, if ever.
Cooper, who has been on the island only a short time, still faces the rule that those who don't face their past are placing themselves in danger. Short of saying Sawyer's mom was easy, Cooper does everything in his power not to repent or to feel remorse for what he did. On the other hand, he thinks he's in hell, so what good would repenting do? His story getting to the island offers another glimpse into just how powerful Mittelos/The Others are in the outside world, that they can get someone that easily.
Unlike the common cliché, the test for Locke was to see if he could kill his father, not find the strength to spare him. This incident makes us question exactly what they mean when they call themselves "good people" if they're willing to let someone, albeit a bad guy, be murdered in cold blood. If more was known about The Others this may be clear, but it seems as though it'll be some time before that happens. Perhaps they are the extreme Locke is in danger of becoming.
Richard makes a fair assessment that the incident served to embarrass Locke in front of The Others, who are in awe of his miraculous healing. Ben's jealousy has manifested before, but now it's clear that he is fighting for his leadership role in The Others. Richard, who seemed to be a neutral force among The Others, stages a minor coup by giving Locke the key to Cooper's death, and by that, further access to The Others.
While Locke no longer has his father hanging over him, his quest to the heart of the island is troubling. He no longer cares for anyone but himself. It doesn't matter to him that Sawyer has to kill again, so long as it helps Locke achieve his perceived destiny. Compare this to Locke from the end of the second season, where his lack of faith in the island caused him to disregard everyone, with near deadly results. This time the pendulum has swayed to the new extreme.
His need for acceptance is also a major factor in his story. He did not move on after his father's death (symbolized by his Christ-like bearing of the body in the end), but replaced his desire for a meaningful relationship with his father with one with Ben. Despite their shaky relationship, Locke somehow thinks Ben is key to getting what he wants. Although Ben is jealous of Locke's connection to the island, he is still a master manipulator, getting Locke to dismiss that notion. Ultimately Locke will have to return to the person we first met in the beginning, only without the need to have someone's approval, if he is to have peace.
It was about time we saw The Black Rock again. One of the great surprises of the end of the first season was the reveal that The Black Rock wasn't literally a black rock. Its strange history was explored on "The Lost Experience", but I won't go into detail here. Locke's decision to bring Sawyer there is also a worthy topic (it may be because none of the remaining hatches Locke knows of have a room that would serve that function).
Although no explanation is given to how she got out of the Barracks or what she did after seeing her daughter, Rousseau's cameo was a kooky treat. Considering she never returned with the crate of dynamite, she must have something big planned. It would make sense for her to be more calculated in her attempt to get her revenge against The Others, and that would require pooling all her resources.
The "old place" the Others take Locke to, with a pillar used to hold Cooper captive, could be connected to the infamous four-toed statue from "Live Together, Die Alone". The architecture could easily have been from the same era, and there's no confirmation or denial that the foot is nearby. It hints again at the larger history of the island: one that goes beyond Dharma's arrival in the 70s. One thing that should be addressed eventually is what prompted the mass exodus from the Barracks and why were the Ruins the destination, but that may be for another episode.
Like The Others' camp, divisions are forming over the new arrival. While they would've gone to Jack immediately before, now they are keeping secret in Hurley's tent. Getting Sayid involved was a wise choice since he is the highest profile anti-Other of the castaways still on the beach, not to mention his unequaled ability to read people. This technique doesn't make him friends with Naomi, as he gets rather confrontational when he asks if the search party can corroborate any of her story. Since it is "Lost", it would make sense for her to have some past errors and sins.
Obviously, the secret keeping is going to be very costly for the group, as seen when Kate finds out about Naomi and confronts Jack about what his friends are doing. For the first time Jack knows what his allignment with Juliet is costing him in terms of his leadership status in the group. Jack's ego clearly clouded his judgment. It never occurred to him that spending a week and a half with The Others would make some people suspicious of his motives when he got back, considering what happened with Michael?
Juliet hints at a master plan she has concocted with Jack, but he for some reason shuts her down. Ironically, he wants to be taken on faith rather than openly give out what these plans are, even to trusted allies like Kate.
Much like Locke, this episode is the darkest "Lost" has ever been. Considering how obvious the reveal of the episode was, the way it played out more than made up for it. As the season winds down, the stakes are continually being raised and character's roles are being challenged, which has been fascinating to watch.