Other mistake: Sloan arrived at the station to destroy the cure, and he and Bashir discuss the fact Sloan has to know what it is to be able to find it in Bashir's lab to be able to get rid of it. Sloan counters he could destroy the whole lab, and Bashir dismisses this as not subtle enough for Sloan. Obviously they've both forgotten that Bashir has perfect memory, so he'd need to be killed to get rid of the cure as well, not just destroy the lab. Something which Bashir would have brought up to back his point up, or Sloan could have used to defend his idea, destroying the lab with Bashir inside, getting rid of both.
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?
Factual error: When Major Kira was introducing Lieutenant Commanders Dax and Worf to the arriving Trill scientists, she introduces them as Commander Dax and Worf. While in informal conversation, they could be addressed as Commander, when making formal introductions, the person making the introductions would use their full proper rank. This is an error that no ranking officer would make, especially not twice. (00:03:10)
Continuity mistake: On the old Enterprise bridge, Sisko is shown at a bridge station, and the person next to him, close to Dax's position, is wearing a gold shirt. When Kirk comes onto the bridge, the person next to Dax now has a red shirt, which was the original crewman's shirt in TOS.