Starfleet reassigns the Defiant crew to a stolen Jem'Hadar fighter to infiltrate Dominion space. Bashir brings up a point that is not expounded upon: it would make more sense to take the Defiant in. It is equipped with a cloaking device so it would be superior at infiltration, and the crew is already familiar with its systems so their won't be a steep learning curve on a sensitive operation. The admiral's reasons for transferring the Defiant's crew to the Jem'Hadar ship are never revealed. It cannot be that the Defiant is needed on the front lines, as the Defiant is kept orbiting the starbase, unmanned and unused.
Correction: It may not have been verbally explained but the mission itself makes it evident why the Defiant wasn't used, the mission doesn't just require infiltration of Cardassian space but also for the supply depot to lower its shields. They destroy the station by transporting a bomb to the supply depot hidden inside a container, the Defiant would need to decloak in order to beam something on the depot and the second they decloaked the depot would raise their shields. Plus Dominion sensors have been shown to detect cloaked ships at close range, and they likely have gravitic sensor nets & a tachyon detection grid along their borders to detect cloaked ships, just like the Federation does along the Neutral Zone to detect cloaked Romulan ships.
Correction: It may not have been verbally explained but the mission itself makes it evident why the Defiant wasn't used, the mission doesn't just require infiltration of Cardassian space but also for the supply depot to lower its shields. They destroy the station by transporting a bomb to the supply depot hidden inside a container, the Defiant would need to decloak in order to beam something on the depot and the second they decloaked the depot would raise their shields. Plus Dominion sensors have been shown to detect cloaked ships at close range, and they likely have gravitic sensor nets & a tachyon detection grid along their borders to detect cloaked ships, just like the Federation does along the Neutral Zone to detect cloaked Romulan ships.
Starbase 375 is scaled incorrectly when seen next to the Defiant. The base appears incredibly small when its size is compared to the "tough little ship," barely larger across than the Defiant. When one of its interior hangars is seen later in, it is much larger, easily able to accommodate a Jem'Hadar fighter. A station the size of the exterior shots could not fit a ship that size within it.
There is a small white triangle in the lower right corner of the screen as the Defiant crew's stolen Jem'Hadar fighter prepares to go to warp after its skirmish with the USS Centaur. The white blemish remains in the corner as the camera pans, but disappears as the fighter goes to warp.
It has been mentioned that this is the final episode to use studio models of ships, future episodes use CGI. This is apparent when a closeup view is shown of the stolen Jem'Hadar fighter approaching the supply depot, two Phillips head screws can be seen amidships on the dorsal hull. On the models (both production and retail replicas) the screws are used to attach the dorsal "V-shaped" aft section onto the bulbous ventral section under it.
When Ducat tries to seduce Kira Nerys he addresses her as "Kira". Bajoran naming custom is Family name Given name so he likely would have called her "Nerys" in this intimate moment.
Garak suggests that he wear the viewscreen headset, as he believes it is more compatible with Cardassian physiology based upon having seen Gul Dukat wear one in "Call To Arms." In "Call to Arms," Dukat and Weyoun did not wear headsets. They wore a type of shoulder harness with an arm that held the lens in front of their face.
Garak is confused about how long it will take to get back to Federation space without warp drive. While he may not know the precise measurement, he was an intelligence operative with the Obsidian Order, and in general is a citizen of a warp-capable species. He would know the time factors involved in traversing space without faster-than-light engines.