the story: Bashir and O'Brien become prisoners of the Jem'Hadar, but a rogue faction that wishes to be released from their Founder-engineered drug addiction.
what it's all about: "Hippocratic Oath" is the point where viewers realize that Paramount probably mandated a more episodic feel to the series than the serialization that had crept into Deep Space Nine in the third season. This mandate would obviously be negated later on, but "Oath" betrays how much pushback had affected the producers, because while dealing with a crucial part of the show's mythology, it's never revisited despite the rest of this season and three more remaining. Dropped elements rarely happened in Deep Space Nine without good reason or some satisfactory conclusion. That simply isn't the case with "Oath."
In the third season the Jem'Hadar's drug addiction was introduced in "The Abandoned," part of the early part of that season in which the producers were trying to square with the more episodic tradition of the franchise despite playing with major new serialized elements of Deep Space Nine itself. "Oath" is a kind of follow-up to "Abandoned," but it takes the form of a new conflict between Bashir and O'Brien, who had finally become bosom buddies despite a rough start to their working relationship. It creates great drama, but in hindsight it also seems random and a little forced, dark for the sake of being dark.
There's a Jem'Hadar soldier introduced, the leader of the rogue faction, who could've easily become a recurring character, played by the ever-dependable Scott MacDonald, in arguably his best Star Trek performance among a whole host of roles spent buried under layers of prosthetics, from Next Generation to Enterprise. He's arguably the most sympathetic Dominion figure the series ever featured (other than the stray rogue Weyoun clone or Cardassian defector like Damar). Maybe for that reason he couldn't return, since the Dominion arc was still in its infancy at this point, so it was good enough to demonstrate, among the least likely component of this new enemy, that there was a chance for hope within it. (Incidentally, the whole Xindi arc from Enterprise's third season is like the Dominion arc condensed, and so "The Shipment" is a better version of "Oath," if you want to see this series in improved form.)
All of which is to say, I just don't think this one worked, both in the short- and long-term, nearly as well as it should have, and it's all down to a temporary retraction of what was to define this series: its dedication to serialized storytelling. "Oath" is an example of how not to do it.
A subplot involves Worf's attempts to find his place aboard the station, as he clashes with Odo over one of the series' oldest narratives: namely just about anything Quark tries to do. It's an obvious story to do, and so it makes sense not to have constructed a whole episode around it.
- franchise - Medical dilemmas are a fact of life in Star Trek.
series- Doesn't reflect well on the overall legacy of Deep Space Nine.
- character - At least pairs Bashir and O'Brien for their first story together since the second season.
essential- It's too dark, even for a dark Trek.