More relevant dialogue from DS9 pertaining to Section 31, this time from "Inter Arma Enim Silent Leges"...
The Deep Space Nine Transcripts - Inter Arma Enim Silent Leges (chakoteya.net)
[Bashir's quarters]
SLOAN: Section Thirty one is extremely interested in this conference of yours. However, the Tal'Shiar will be handling the security arrangements, so we have virtually no chance of using any technical assets to gather intelligence. As a result, we'll be forced to rely on organic assets, like you. Your mission is to gather data on the Romulan leadership. In essence, we want you to take the pulse of their government. No pun intended.
BASHIR: You want me to spy on an ally.
SLOAN: To evaluate an ally. And a temporary ally at that. I say that because when the war is over, the following will happen in short order. The Dominion will be forced back to the Gamma Quadrant, the Cardassian Empire will be occupied, the Klingon Empire will spend the next ten years recovering from the war and won't pose a serious threat to anyone. That leaves two powers to vie for control of the quadrant, the Federation and the Romulans.
BASHIR: This war isn't over and you're already planning for the next.
SLOAN: Well put. I hope your report is equally succinct.
[Captain's office]
BASHIR: Odo's checked all the security logs. There's no indication of how Sloan got aboard or where he went.
SISKO: Can't say I'm surprised. From what we've seen of them, Section Thirty one is very meticulous in covering their tracks. I had a conversation with Admiral Ross this afternoon. He and I both agree that the Romulan conference is too important to cancel.
BASHIR: What about me?
SISKO: Starfleet Command has promised to send the expert on Dominion biogenic weapons and Ketracel white to the conference. Since that's you, you go. And we want you to carry out your assignment. Make a few discreet observations on the Romulan leadership and then wait for Sloan to contact you again.
BASHIR: Somehow, I don't think giving Sloan any information is a good idea.
SISKO: That was my instinct as well, but after talking to Ross I think we might have an opportunity here we can turn to our advantage. Officially, Starfleet Command has said that they are appalled at the very notion that an organisation like Section Thirty one might exist, and that they plan to get to the bottom of this entire business.
BASHIR: And unofficially?
SISKO: They have quietly pushed the investigation aside, which means either they don't take Section Thirty one seriously or someone at Starfleet Command is protecting them.
And now dialogue from "When It Rains"...
The Deep Space Nine Transcripts - When It Rains... (chakoteya.net)
[Infirmary]
BASHIR: The dispersal pattern in this resonance scan. I've seen it before.
O'BRIEN: What do you mean?
BASHIR: When I first came to the station, I had to familiarise myself with Odo's physiology. Doctor Mora was kind enough to share his data with me. This looks like the scan he did when he first found Odo.
O'BRIEN: Are you sure? There's a lot of numbers there.
BASHIR: I saw it with my own eyes not seven years ago.
O'BRIEN: You really are genetically enhanced, aren't you.
BASHIR: According to the date, this scan was done when Odo was at Starfleet Medical.
O'BRIEN: Two different scans can't have exactly the same dispersal pattern?
BASHIR: It's impossible. Someone took Mora's results and built up a phony medical workup around them. This isn't Odo's file. They sent a fake.
O'BRIEN: I can't believe Starfleet Medical would actually make up a fake file just to throw you off.
BASHIR: You're right. It isn't something Starfleet Medical would do.
O'BRIEN: Are you thinking what I'm thinking?
BASHIR: Section Thirty One.
O'BRIEN: An organisation that's prepared to do whatever it takes to protect the Federation wouldn't even blink at doing something like this.
BASHIR: They don't want me to find a cure. They're afraid the Founders will get hold of it.
O'BRIEN: And to keep that from happening, they're willing to let Odo die.
[Infirmary]
O'BRIEN: I don't know, Julian. If Section Thirty One is involved in this, maybe we should tell the Captain.
BASHIR: We've been over this, Miles. If we tell him, he'll have to report it to Starfleet Command. Thirty One'll certainly get wind of it and once they realise we figured out the files are fake, they'll take steps to make sure we don't find a cure.
O'BRIEN: I see your point. What steps do you think they might take?
BASHIR: Believe me, we don't want to find out.
[...]
BASHIR: Hang on, hang on, I'm just trying to figure out when Odo became infected. I analysed the sample he left and mapped out the life cycle of the virus. I'm programming the computer to calculate just how long it took for the virus to achieve its present level of concentration.
O'BRIEN: That makes sense. According to that, he was infected over two years ago?
BASHIR: More than that. I just don't understand. I assumed he became infected when he Linked with the female shape-shifter.
O'BRIEN: But if it happened that long ago, how come he hasn't shown any symptoms before?
BASHIR: Good question. Got it. Stardate 49419.
O'BRIEN: Almost three years ago.
BASHIR: Wait a minute. 49419. That's the day that Odo was at Starfleet Medical.
O'BRIEN: You sure?
BASHIR: Yes. My god. No wonder Hilliard wouldn't let me see the file. Section Thirty one must have created the virus, infected Odo, and then used him as a carrier.
O'BRIEN: So that when he Linked with another changeling, he'd pass it on, and eventually the entire race would be infected.
BASHIR: Thirty one isn't just trying to stop us from finding a cure. They're trying to cover up the fact that they set out to commit genocide.
O'BRIEN: Well if they gave Odo this disease, then they must have a cure.
BASHIR: We have to find a way to get our hands on that cure.
O'BRIEN: Before Thirty One gets their hands on us.
Dialogue from "Tacking Into the Wind"
The Deep Space Nine Transcripts - Tacking Into The Wind (chakoteya.net)
[Infirmary]
O'BRIEN: Mind if I ask you a question about Thirty One?
BASHIR: Go ahead.
O'BRIEN: Well, if you were to find the cure and they got to know about it, what do you think they'd do?
BASHIR: Well, I imagine they'd be very concerned. The very existence of a cure would jeopardise their plan to eradicate the Founders. It wouldn't surprised me if Sloan or another operative turned up here on the station to destroy my work. What are you getting at?
O'BRIEN: I think you should send a message to Starfleet Medical saying that you have found the cure.
BASHIR: You're trying to lure someone from Section Thirty One?
O'BRIEN: Yeah. That's right.
BASHIR: What happens when this operative gets here?
O'BRIEN: We capture him. Then we figure out a way to get some information out of him.
BASHIR: He may not know anything about the disease.
O'BRIEN: Maybe not, but I bet he knows who does. What do you think?
BASHIR: I think it's a plan. A very good plan. When did you get so devious?
O'BRIEN: I've been hanging around you too long. Let's just hope this works and we can cure Odo. That's all I care about.
BASHIR: Me too, Miles.
Finally, dialogue from "Extreme Measures"
The Deep Space Nine Transcripts - Extreme Measures (chakoteya.net)
[Sloan's office]
(Button 48 opens the door to reveal a room with pieces of paper all over the floor. Sloan is reclining in his desk chair.)
BASHIR: Sloan?
SLOAN: Welcome to Section Thirty One, gentlemen.
BASHIR: You know exactly why we're here.
SLOAN: You don't really expect me to help you.
(Bashir starts going through a pile of PADDs.)
SLOAN: You sure you want to throw that one away?
BASHIR: I'm collecting medical information, not surveillance reports.
SLOAN: It's not just any report. That's on Jaresh-Inyo.
BASHIR: Former President Inyo?
SLOAN: The one and only.
BASHIR: My God. Thirty One had a man in his cabinet.
O'BRIEN: Don't let him distract you.
SLOAN: Just one of the little nuggets lying around in this once tidy room. You'd be amazed at what you could find.
BASHIR: Current operations on Kronos. Chancellor Martok would love to get his hands on this.
O'BRIEN: Julian, look at this.
BASHIR: Radodine, lidestolinine, asporanine, adenine. That's it.
(Big rumble and sparks.)
O'BRIEN: I think it's time we got out of here.
BASHIR: Hold on a moment.
O'BRIEN: What for?
BASHIR: These files, they contain all of Sloan's memories on Section Thirty One. With this information we can destroy the entire organisation.
O'BRIEN: That'll have to wait.
SLOAN: It's not that simple, Chief. There is no building, no room like this in the real world. Section Thirty One has no headquarters. These files, they exist only in the minds of a very select group of people, and I happen to be one of them. If you really want to destroy Section Thirty One, it's now or never.
BASHIR: He's right. This is a once in a lifetime opportunity. We can't pass it up.
O'BRIEN: Julian!
BASHIR: What?
O'BRIEN: Listen to me. He wants us to die with him. If we die, Odo dies too!
SLOAN: All my secrets are yours for the taking, Doctor. If you want them badly enough.
O'BRIEN: Odo needs you, Julian. He's counting on you.
SLOAN: You're making a terrible mistake, Doctor.
BASHIR: I don't think so.
That covers all the relevant dialogue from DS9 about Section 31 as it pertains to their having infected The Greak Link.
