The Intendant, Smiley and the mirror Garak are the only mirror universe characters to appear in all of the mirror universe episodes that take place on their side of the wormhole.
This episode marks the first appearance of the mirror universe on Star Trek: Deep Space Nine.
Nitpick: When Kira and Bashir emerged from the wormhole in the mirror universe, it took them three hours to reach the station as it orbited Bajor. As they escaped the station and headed home, they reached the wormhole in seconds.
Kira: (learning Mirror Sisko is a freebooter for the Intendant) And why do you deserve this special treatment?
Mirror Sisko: I suppose because I amuse her, and she's not easily amused. And it seems that you amuse her, too.
Mirror Garak: (as Quark is dragged away for execution) I shall miss him. He always let me win at Dabo.
Smiley O'Brien: (to the Intendant) This man is a doctor where he comes from. And there's an O'Brien there, just like me... Except he's some kind of high-up chief of operations. And they're Terrans. Can you believe that? Maybe it's a fairy tale he made up, but it started me thinking how each of us might have turned out, had history been just a little different. I wanted him to take me with him because, whatever it's like where he's from, it's gotta be better than this. There's got to be something better than this.
Mirror Sisko: What do you care about Terrans' freedom?
Kira: I care about freedom! What I don't understand is why you don't care. Why the only one I have met on this station who seemed to give a damn was a Ferengi toad named Quark!
Intendant: I know very little about where you come from, but from what I've heard, I think your kind has a lot to learn.
Bashir: (defiant) We've got a lot to learn?! That's a laugh.
Intendant: Quiet! On this side, Terran workers do not speak to their superiors as you do. They certainly do not murder them!! He was the only one of his kind, the man you killed. Do you realize that? He is irreplacable. No one ran that operation as efficiently as he did. No one kept order among the workers as he did. This is my reward for treating you Terrans with the least respect? Very well. I can learn for my mistakes. You want to set an example, Garak? Use him. Set an example. For all Terrans. Let him die slowly in public view on the Promenade. Let his arrogant Terran voice pleading for mercy echo through the corridors for all Terrans to hear!
Intendant: Have you lost your mind?!
Mirror Sisko: No, I didn't lose it. I just... changed it.
Kira: I am Kira Nerys.
Intendant: That makes two of us.
Cirroc Lofton (Jake Sisko) does not appear in this episode.
The writers originally considered having Michael Dorn appear as the mirror Worf, who would have been one of the mirror Kira's many thugs. The mirror Worf would later be seen in "Shattered Mirror" and "The Emperor's New Cloak" (with a much higher status).
Major Kira: Through the looking glass, Commander.
Through The Looking-Glass, And What Alice Found There is an 1871 children's novel by Lewis Carroll. It is nominally a sequel to Carroll's previous work, Alice's Adventures In Wonderland, although there is little by way of connection. In the story, Alice passes through a mirror and into a world that is in many ways the opposite of her own, much as Kira and Bashir do when their damaged runabout passes through the wormhole.