
Elizabeth Sarnoff and Christina M. Kim penned an episode that's decent for roughly 40 minutes, then mind-blowing for the next 3-4 minutes. They provided what is consistently pegged as one of the most shocking moments in the series.
I was expecting to be completely underwhelmed the first time around, especially when I learned it was an Ana Lucia-centric. And at first the episode didn't seem all that special. Ana Lucia resigned from the police force in the wake of the Jason McCormack fallout, then took a security job at the airport where she'd eventually meet Christian Shepherd.
If you believe Christian, fate brought them together for "the same reason it does anything, so they could help each other out." And that's ultimately what they did, although it seems Ana Lucia got very little out of the deal.
When their little Bonnie-and-Clyde routine is overwith, Ana Lucia overhears a despondent Jack at the airline counter, which prompts her to call her mother. At that moment I finally began to feel a twinge of sympathy for her.
This is all the perfect setup of course, with Michael just getting back on his feet and learning that Henry Gale was in the armory. If Ana Lucia couldn't bring herself to put a bullet between his eyes, Michael definitely would. It's the moment we've all been waiting for!
"I'm sorry," Michael says. That's the last line he'd utter before The Shot Heard 'Round the Island. Ana Lucia takes a fatal bullet, then before the smoke even clears from Michael's gun he shoots Libby as well. The armory door opens, Gale rises to his feet, and Michael turns the gun on himself.
Silence. Shock. You know something special just happened when you're staring blankly at the television for fifteen minutes after the closing credits.

Michelle Rodriguez was able to stretch the emotional range a tiny bit in Two For the Road, but only at certain moments and certainly not to a level where I was genuinely impressed. She kept the chip on her shoulder until the bitter end, minus one scene in the airport where she tearfully says, "I want to come home, Mom."
Ana Lucia never quite made it home but Michelle certainly did.
Jorge Garcia was disappointing in this episode, delivering line after line with unnecessary long pauses in his stuttering. I get it, he was nervous around Libby, but stuttered speech alone does not effectively convey anxiety and is in fact annoying.
Cynthia Watros (Libby) was the other casualty but she didn't have enough of a role in Two for the Road to assess her acting either way.
Harold Perrineau's performance earns top honors this time around. You appreciate it more after you've seen the shocking ending and then revisit the episode, knowing he's in the process of executing a plan. He certainly knows how to feign surprise and reel someone in — in this case Ana Lucia.
Bonus points for John Terry who ALWAYS does a tremendous job as Christian, even the sloppy-drunk and vindictive version we got to see in Two for the Road.

Two scenes really stand out: 1) Ana Lucia telling Henry Gale to cut himself loose in the armory, and 2) the entire ending sequence. Both were shot so brilliantly and built the suspense to a fever pitch. I love how the smoke from Michael's gun fills the picture for a few moments, with chilling silence all around, then the camera pans behind Michael as Libby approaches the scene. I can't imagine how many takes were required for that sequence.
A random smaller detail: Ana Lucia waiting in the car while Christian approaches the house in Australia. The camera peers through the windshield and everything's blurry until the next pass of the wipers. It's not very profound from a storytelling perspective, I just thought it was a technical and visual treat.

This is a tough one to rank since the first three-quarters of the episode are setup material, some of which is comprised of Ana Lucia flashbacks. But there's no question the payoff is worth it, and every time I see the last few minutes I re-live that adrenalin rush all over again.
Two for the Road's impact on the series is a no-brainer with the abrupt end of two characters over the span of a few minutes (well, Libby survived through the beginning of the next episode but you get my drift). It's also the turning point in Michael's desperate quest to get himself and Walt off the island. Careful what you wish for, Mike.

I've always hated the phrase "mixed emotions" but sometimes it just plain fits. It's certainly appropriate in describing the emotional impact of Two for the Road since it deprived us of Ana Lucia (cause for celebration) and Libby (devastating loss).
I even had mixed emotions when it came to Michael. I've put myself in his shoes and wondered how far I'd go to save my own son, and while I'd like to think I'd never resort to such extremes I definitely think it could drive someone to madness. Michael completely isolated himself and fell into the same sort of darkness that gripped Sayid in the past and Claire in the future.
If shock qualifies as an emotional impact then this episode undoubtedly deserves the high rating.