Rumors of Scorpy's death have been greatly exaggerated -- which is good, because Scorpius' plot pushes this episode just past mediocrity.
The Farscape Wiki has a summary here.
I don't have much to say about the main plot on Moya because the alien possession storyline is very, very standard issue. No -- as I suggested in my opening comment, what really makes this episode at least marginally worth watching is what Justin Monjo does with the characterization of Scorpius.
For the past year (and a little more), the writers have firmly established that Scorpius is evil. When it comes to achieving his goals, you see, Scorpius is frighteningly single-minded. If you get in his way, forget it: you will be destroyed. The thing is, up until this point, the writers haven't yet revealed Scorpius' deeper motives. Why is he willing to mow down everyone and everything in order to get to John? Why is he so obsessed with wormholes?
This episode finally provides an answer -- and said answer sheds a fascinating new light on Scorpius. Granted, he is still evil. Ethics and morals don't really enter into his schemes, after all. But the fact that the Peacekeepers may be facing an existential threat in the near future - and that they've escaped total annihilation thus far because they've lied to the Scarrans about their technical capabilities - does prompt this viewer to reassess her assumptions -- and that translates into a score boost for the writing.
Despite the cliched A-plot, Monjo gets a few bonus points for adding layers to Scorpius.
The performances are pretty good, but not extraordinary.
D'Argo: Crichton, calm down. You're tired. It could all turn out to be nothing.
John: Nothing? I'm bleeding, and I have no wound! So either I'm St. John of the Uncharted Territories, or there's something very, very wrong with me! (Heh.)
D'Argo: We -- what would you like us to do?
John: I want all of you to watch me in case I have another episode - a bleed - whatever you want to call it.
Chiana: I'm sorry. As much fun as that sounds, I don't think so.
John: PIP! STOP! Okay? Y'know -- look, I thought that I was the real me and that that other guy - the-the guy on Talyn - that he's the clone. But I'm starting to think maybe I'm the photocopy.
Chiana: Crichton, this has nothing to do with the split! Just sleep. You'll be fine.
John: No! I'm not imagining this! Watch me - please?
D'Argo: All right, John. Sit down, and -- (Just then, D'Argo sees Chiana and Jool heading for the exit.) Ah-ah-ah-ah-ah-ah! (He quickly stops the girls and steers them back into the room.) Girls, we will all sit down -- and watch John.
Chiana: (petulant) What if I have to piss?
D'Argo: Well then, we will all urinate together.
Chiana: You promise? (LOL!)
Jool: Does anyone know what's going on here?
John: I don't know. You feel any different?
Jool: (tetchy) What do you mean - different? Different like I might have a diseased alien in me different? No - I don't feel like that.
D'Argo: (pleasantly) Actually, now that you mention it, I've been feeling a little angry.
John: That's normal for you. (Heh.)
Braca: You're busy. I'll come back later, sir.
Scorpius: Nonono. Come in, come in. (Braca reluctantly sidles in - and watches as Scorpius plunges the business end of the hypodermic gun into his own neck. There's a pause while the half-Scarran waits for whatever was in the vial to absorb, then he heaves a great, disgusted sigh.) Braca. Why is it that Crichton, a human, can survive wormhole reentry - and a Sebacean cannot?
Braca: Well, perhaps there's some information still hidden in the chip we took from Crichton’s brain.
Scorpius: (thoughtfully) Perhaps. (There's another pause.) Do you know why you're my second in command, Braca?
Braca: No, sir.
Scorpius: Because you don't ask questions. But have you ever asked yourself, Braca - why do they give us so much rein? Hm? Chasing Crichton? Researching wormholes?
Braca: Well, like you said, sir, I don't question High Command.
Scorpius: Would it surprise you to learn that the Scarrans are planning a massive assault against us -- but they haven't, becaaauuuse -- (He leans forwards and says conspiratorially.) -- because they fear our hidden wormhole weapons?
Braca: (with a trace of dread) We have no hidden weapons.
Scorpius: We lied. And I think the Scarrans are beginning to suspect that. High Command reports they've been massing armies. By latest estimates, Scarran warriors outnumber Peacekeeper soldiers 10:1. But if and when they attack, we will lose, Braca.
Braca: Unless we harness a superior weapon.
Scorpius: Yes. Wormhole technology. Without it -- the Sebacean race will be overrun. Thousands of cycles of history -- gone. (So the snake has a reason for his obsession? Iiiiinteresting.)