From “Empok Nor” (5x11)

Nog and O’Brien are back in the cargo back working. Nog wants to know about Garak’s needling. O’Brien is not-explaining when, speak of the devil…

Nog: Chief, why does Garak keep bringing up Setlik III? 

O’Brien: Because he wants to get under my skin. 

Nog: But you were a hero, weren’t you? 

O’Brien: That doesn’t mean I like thinking about what happened then. I was a soldier, Nog. Sometimes soldiers have to kill. 

Garak: Come now, Chief, don’t be so modest. You did a lot of killing. 

Nog: How’d you get in here? Both doors are secure. 

Garak: Secure is such a relative term, wouldn’t you agree? I’ve brought you something, if you don’t mind.  [Another Third Battalion insignia.] I’m sure Pechetti would have appreciated it more, but…

O’Brien: Where did you get this? 

Garak: From its former owner. 

Nog: You killed one of the soldiers? 

Garak: One down, one to go.

Nog’s not afraid of Garak… yet. O’Brien, however, is definitely starting to hearken to his Spidey Senses.