Warning: Fullfor the episode follow...

Someone's smiling like they know something.

Excuse me now while I attempt to put what I just saw into words. I'm readily presuming that having to review Person of Interest's Season 3 finale, "Deus Ex Machina," while still reeling from its effects will be challenging. But I'll do my best.So let me quasi-arbitrarily start at the end then. With the last portion of the episode set hauntingly to Radiohead's "Exit Music (For A Film)." The best use of a song on TV since, well, last fall when Person of Interest used "Hurt" to open "The Devil's Share." An ending that surprised us (after an epic episode that was already full of swerves and thwarted expectations) with the reveal that Root never intended to destroy Samaritan. And that her mission, at the behest of The Machine, was to poke a small hole in Samaritan (the actual number of servers stolen last week shown to be very important here) so that she, Harold, Reese, Shaw, and the three hackers could slip through the grand awakening with new identities.And so last week when it seemed like Collier had circumvented Greer's plans? Well, that was just more misdirection. Masterfully done. I did not see that coming. Nor did I ever consider an ending where Samaritan was actually activated on a national level. That just seemed too destructive. I think I even stated that it was something that the show couldn't come back from. Which would therefore make it impossible to do from a story standpoint. Hah! Shows what I know. And it's exactly because of those reasons that the ending was so heavy and spectacular. Along with the finale scene showing Greer more than ready to take orders from Samaritan! The show essentially allowed Skynet to rise. Allowed for Judgement Day to roll out like a software update.Since I started at the end, let's just keep that going and move backwards along the episode's timeline. Greer was behind Collier's texts. Another straight-up "mind blown" moment. Again, last week I assumed it had to be someone we'd met before, but I never figured it was someone in the same room. And what a final insult to Collier, finding out he was nothing but a puppet in Big Brother's grand scheme. Now forever framed as a terrorist behind a deadly bombing. Sure, the show cheated a little with the reveal that Harold basically confessed to building The Machine to a bunch of cameras that were broadcasting into nothing (which was it's own stand out "holy s***" moment), but it still fit because it was all Greer's doing. It was a shell game and we just had our eyes on the wrong target.The entire court scene was still fascinating though. And, again, very Batman-esque. A deadly trial where death verdicts were handed out on the spot courtesy of a shotgun blast. And it only doubled Collier's tragedy in the end because he also knew that none of his efforts to expose any of the people behind Northern Lights meant anything. He'd not only wasted the past four years of his life, but he aided his greatest enemy in the process.So then, from that scene on the roof, I thought "Wow, Greer's behind all of it. Good thing Root's about to blow his plans out of the water." But I was way off. Again. And it was for the best too. Because if Greer had been immediately defeated then the twist would have never felt big enough to resonate. Having him win made it all the more dastardly. And his line about the humanity's near future resembling the myths of the ancient Greeks? "A pantheon of super-intelligent beings who will watch over us, using human agents to meddle in our affairs." Nicely, and terrifyingly, put.I think we all assumed the show would end on a cliffhanger, like POI's past season finales have, but I don't think we were prepared for this big of a game-changer. And I love how the reveal of Decima being behind Vigilance retro-actively tied everything together for the season, post-HR. It explains so much. How Vigilance always felt like party crashers - the extra danger - in most every shoot out scenario. They'd show up to interject themselves into the mix, making everything go from bad to worse.There were other great moments here too, aside from the huge sweeping surprises. Root plus Shaw always equals a good thing. And Shaw's triangle choke hold equals a perfect thing. Their bickering-slash-flirting always works perfectly. And Hersh may have not stopped the bomb from blowing up, but he damn sure went out like a badass hero. And Fusco not needing a new identity was perfect considering that when Reese and Hersh mentioned The Machine he said "What machine?" Sometimes I forget that he's still clueless about certain things.