Looks like Locke owes Jack a Coke.
Yep, the button is meaningless. Pushing the button does nothing, except that some Hanso douchebags in yet another hatch are going to be observing you. Locke and Eko, who are supposed to be chasing after Henry -- who, according to Michael, shot him and the late Ana-Lucia and the soon-to-be-late Libby and himself -- are instead led through incredibly helpful dream sequences to Pearl Station, which is an abandoned yet almost fully functional observation station. Locke takes it hard that nothing in his "pathetic" life (his word) means anything. But Eko says the proof of the experiment means more than ever. This makes no sense, until you consider Eko's Catholicism, and then you think, "Yeah -- following usually inconvenient and always futile rituals for the sake of simulating some sort of purpose for your existence would be right up Eko's alley."
Except in flashbacks it's confirmed that Eko didn't honour his dead brother by actually becoming a priest. But Eko's faked papers are good enough for the monsignor, who wants him to investigate an alleged miracle (Skeet's not available?). Supposedly some girl died but came back to life the next day, a theory rejected by her father, Claire's psychic, who admits to being a fraud who gathers intelligence on people. Eko leaves the hoax alone (professional courtesy from one charlatan to another), but just before he boards Flight 815, the girl tracks him down at the airport to give him some message from his brother, beyond the grave, some nonsense about what a good priest Eko is, even for a phoney. Hey, remember when there was supposed to be all perfectly good explanations for the goings-on on Craphole Island? No supernatural nonsense?
Jack sends Kate with Sawyer to get some heroin to ease Libby's suffering, with the idea being he'll have to reveal where his stash is (since it also holds the guns). Turns out Sawyer's kept the guns with him the whole time, buried on the beach! Is that really all that surprising?
And then Libby dies, Hurley cries and apologizes for his FEMA-level incompetence at picnic planning, and Michael can stop pretending to be concerned about her condition, leaving him more time to hang out in the armoury and look around all evil.
Yemi's sitting at a computer, so we're still in a dream sequence. He turns toward Eko and stands up, and an overjoyed Eko starts blubbering that Yemi was right (presumably about how posing as a priest in order to smuggle heroin is bad? Well, duh) and he wants his brother's forgiveness, but Yemi interrupts him to say, "The work being done in this place is important, Eko. It is more important than anything. And it is in danger." Like Ana-Lucia, Yemi says Eko must help John: "He has lost his way. You must take him to the question mark."
The bunker beeping starts up again, and Yemi glances at the timer, which consists of five shuffling question marks. He quickly types in the numbers -- except that the keyboard consists of nothing but question marks. Having settled the timer down, he continues instructing Eko: "John will not want to show you. So you must make him." Eko turns to go, but Yemi grips his arm and says there will be many distractions, but Eko must look past them. Meanwhile, the whole bunker is shaking like a Sir Mixx-A-Lot video. "What is done is done," says Yemi, and he asks if Eko says he understands. Eko says he does, and Yemi smiles, but there's one more thing: "Bring the axe."
Eko wakes up, sitting straight up in the middle of the night, breathing heavily. Nearby, Charlie stirs, asks him if he's all right. Eko clutches his cross. Then he grabs his axe, and says, "I need to find John." Anything to say to that, Charlie? You're not concerned by this?