Plot hole: Just after the Kelleran soldiers kill all the scientists, O'Brien tries to contact the runabout Ganges for a beam out. Unable to contact the Ganges, he and Bashir use the T'Lani cruiser's transporter to beam down to T'Lani III. He could have used the cruiser's transporters to beam to the Ganges instead (it wouldn't have had its shields up as it was unoccupied and was closer to the cruiser than the planet) allowing them to escape back to the wormhole and DS9, instead of having to await rescue on the planet.
Character mistake: When Nedelle collapses, everyone looks to Jadzia to save her and she says she can't. Why do they think Jadzia can save her? She isn't a doctor, and the Dax symbiant was never a doctor either. They are on board a Federation ship, with a Federation crew, why do they not call The Ship's doctor?