Marko Ramius taking out an enemy sub, with his own totally unarmed.
The President, National Security Advisor Jeff Pelt, Director of Central Intelligence Arthur Moore, Deputy Director Jim Greer, and DDO Robert Ritter successfully tricking the Soviets into buying a totally false cover story, and flushing out a long standing traitor.
Skip Tyler comes up singlehandedly with a plan to convince the Russians that the Red October has sunk. Even more impressive, he comes up with the whole plan about thirty seconds after finding out about the defection!
Admiral Greer: Your full name is Oliver Wendell Tyler? Well, son, if you were named after Harry Houdini instead of a justice of the Supreme Court, I'd... What do you have in mind?
The best part is the overall coup, not just the capture of the submarine and officers, but the other factors surrounding it. The CIA gets a (mostly) intact Soviet missile submarine, along with all the equipment and (most) of the missiles. They get the officers, one of whom wrote the book for all other Soviet submarine captains, so they have details on Soviet tactics and doctrine. They use the crisis to find a long-standing mole, who they then turn into a double agent, and they use that to convince a Senator that's been giving them trouble to resign to avoid a scandal. And to top it all off, they then use a massive disinformation campaign by sending out their agents to find out what the hell happened in the Red October event, rather than (as Ritter says) bringing everyone in after a successful operation, making the Soviets think that the US is just as clueless as they are, and force them to keep spending time and resources looking for a story that doesn't existnote As Judge Moore says, the Soviets can either believe that one of their most respected and esteemed citizen soldiers, Ramius, defected from his privileged life in the Soviet Union, or they can believe that an intelligence operation managed to cause chaos by getting Ramius to act on false orders, and given the choice, the Soviets will believe the second option over the first. Because there's no real evidence supporting the first other than Ramius' flamboyant and seemingly-out-of-character letter for Padorin, and plenty of "evidence" supporting the second, the Soviets will come to the wrong conclusion. And they end up leaking information that says they were tracking the Red October from Iceland, both to convince the Soviets that the US was hiding something (and misleading them about what they were hiding), and to prevent the construction or improvement of the caterpillar technology. All because one submarine captain's wife died.
Jack successfuly taking out the GRU agent hiding in the Red October's missile bay.
Worried about the Soviet fleet sailing close to the Eastern Seaboard, the US sends them a message: a flight of four A-10 Warthogs boxing in Kirov, the fleet flagship, with flares standing in for weapons delivery — including anti-tank munitions and the 30mm Avenger cannons they're packing. What makes it even more awesome is that the A-10s were flying at low altitude, almost above sea level, and were being used for the naval strike because they were the first available unit - and antishipping isn't an A-10 mission, but A-10s carry weapons that can kill heavily armored tanks, and what can kill a tank can hurt an unarmored ship.
One for Tom Clancy: his novel was so accurate admirals wondered if he was a spy, and he showed them the research done from the library. He's been positively portrayed as an expert ever since.
It's rare for a submarine to get its own crowning moment of awesome, but The Reveal on the Red October is a definite example.
Ramius getting his entire crew to sing the U.S.S.R.'s National Anthem. Even more so when he tells them to keep singing after one of his officers raises concerns about their noise level.note Even better when you realize Ramius is trying to get people to track the sub while "cloaked" with the caterpillar drive.
Borodin: And the singing?
[Ramius looks around, contemplating the noise level]
Ramius: Let them sing!
Ramius' navigating blind through underwater canyons as part of an underwater Canyon Chase also qualify. It's exposited that Soviet captains get extremely accurate undersea maps of the canyons with precise times to follow for each leg to allow them to do this safely - which Ramius then proceeds to throw out the window as he navigates round the Neptune Massif by the seat of his pants.
Lt. Kamarov: Turn plus thirteen, plus fourteen, plus fifteen seconds! Captain, if we're out of position by so much as a boat length...!
Related to the above quote, Ramius is also trying to evade an air-dropped torpedo while still navigating the sub through the canyon; he's deliberately overshot the turn so that when he does finally swing round Neptune Massif, the torpedo's SONAR is confused by the canyon wall, and tracks that rather than the sub. That's right, he pulls off a freaking Wronski Feint with a 40 thousand-something ton submarine!
Related to the above, Kamarov's epic Badass Boast:
Kamarov: Stop pissing, Yuri. Give me a stopwatch and a map, and I'll fly the Alps in a plane with no windows.
Yuri: (Nervously) If the map is accurate enough...
How Jack gets on the Dallas. The guy terrified of flying gets on a helicopter in the middle of a storm to be lowered down on a rope in order to get to the sub, and when it seems the maneuver has failed and they start reeling Jack back in, he waves his arms emphatically to get them to stop. When the pilot ignores him, he, completely straight-faced, releases himself from the rope to fall into the icy cold water below.
Jack: *coughing* How do you do, captain? It's a pleasure to be aboard.
"Give me a ping, Vasily. One ping only, please."
The intervention of the USS Dallas, drawing off Tupolev's torpedo and then dropping decoy countermeasures to spoof the torpedo and performing an Emergency Main Ballast Tank Blow, which not only gets them out of the torpedo’s way, but also causes the 7,000-ton Los Angeles-class submarine to literally fly out of the water. They may not have been allowed to fire at the Russian sub, but they sure outmaneuvered it.
Jones: WAY TO GO, DALLAS!
Followed by the Dallas practically flying out of the water, as the EMBT Blow is an emergency procedure that blows all ballast tanks dry, cranks the diving planes to turn the boat’s steeply upwards, and redlines the engine. This procedure is designed to get a crippled submarine to the surface even if she’s taking water.
Sonarman Beaumont: Torpedo is in acquisition, range 500 yards and closing! You've done it, Mr. Thompson!
Lt. Cdr. Thompson: I hope to Christ this works! Alright, Chief, put us on the roof.
COB Watson: Countermeasures station, on my mark! Five, four, three, two, one; release countermeasures, emergency blow!
Lt. Cdr. Thompson:Come on, Big D, FLY!
The above maneuver naturally leads to the rescued crew of the titular submarine, who are ignorant of Ramius and co.'s defection, to think their captain has chalked one up for Mother Russia.
Crewman (in Russian): Captain's scared 'em out of the water!
Captain Mancuso has the final CMoA by blowing up the enemy submarine with their own torpedo.
Mancuso: [calm and deliberate] Right full rudder, 30 degree down angle.
Jonesy: This one’s gonna be close!
What is the last thing that the Soviet attack sub "sees" before it is blown up? The Red Star painted on the nose of its own torpedo!
Ramius' speech upon revealing the orders to the crew, especially this bit.
Ramius: "It brings me back to the heady days of Sputnik, and Yuri Gagarin, when the world trembled at the sound of our rockets. And they will tremble again, at the sound of our silence."
Sonarman Jones, facing the dilemma of a Soviet sub with a revolutionary top secret stealth propulsion system, invents a way to detect and track the enemy in only a few hours.
And all this based on the fact that he thought he heard singing as the sub vanished from sonar, and the only sound the sonar was able to pick up, the computer told him was a "magma displacement." The man's got good instincts.
Mancuso gets the assist on this, as he's willing to listen to Jones' crazy-sounding theory (Jones himself seems to know how far-fetched it seems) and formulates his plan while allowing Jones to do what he's clearly proven himself good at.
Mancuso: If I get you close enough, can you track this sucker?
Ryan and Ramius are forced to take cover in the Missile Room when the Mole opens fire on them. As Ryan prepares to break cover, he looks up at what he had sheltered behind, and the camera pans back to reveal it is one of several nuclear missiles launch tubes, as an ominous choir beings chanting to highlight the sheer amount of destructive power in the room with him.
One for Ryan at the end; despite insisting all throughout the movie that he is not a CIA field agent, he manages to get the drop on The Mole before he can detonate a missile within Red October, gives him one warning in Russian ("Ostav eto v pokoye!" - 'Leave it alone'), and when it becomes obvious that The Mole won't back down, Ryan - a former Marine - doesn't even hesitate to take care of business, saving the ship.
The idea of Sean Connery and Tim Curry starring in the same movie, and their characters having interactions.
While running towards a torpedo and against Mancuso advise, Ramius not only quizzes Ryan about Ryan's books as the torpedo is about to hit their sub, but is also able to impugn him intellectually.
Ramius: Oh, I know this book. Your conclusions were all wrong, Ryan. Halsey acted stupidly.
Heart-wrenching and powerful before you even know the lyrics.