I posted a theory here years ago that Pria goads Mercer into destroying the wormhole on purpose, that the cold "you'd still be that messed up guy who can't get over his ex" line was engineered to push him to do it. I always had one problem with my own theory. If she wanted the wormhole destroyed, and destroying it erases her, why would she want that? I rewatched this week and I think I finally have the answer.
As I originally posited in my earlier theory, Pria was never really *just* an antiques dealer. That job was cover. She came back through the wormhole from a future plagued by the Kaylon, the machines that outlived their makers, and her target was never the Orville. It was Isaac.
Start with the ending, because the ending is the tell. The way the crew "beats" her is by destroying the wormhole, which erases her and every piece of tech she brought with her. Sit with what that means. If her real goal was stealing the ship, being erased along with all of her equipment is total, complete failure. She loses everything she came for. But she does not fight that outcome. She provokes it. A thief who wants a prize does not maneuver everyone into deleting the prize and herself along with it. A deep cover operative does exactly that. She does one specific thing, then vanishes with no forensic trail left behind. Destroying the wormhole is not her defeat. It is a clean extraction that scrubs the evidence. That only makes sense if the ship was never the point.
So what was the point? Watch the scene where Isaac interfaces with her control device. He touches it, gets blasted, shuts down, and reboots. In the moment we read that as Isaac trying to stop her and getting repelled. But in computer tech, a write to a device followed by a forced power cycle is what a firmware flash looks like. And ask why a generic ship hijacking tool would have a mechanism that specifically zaps and reboots a Kaylon. It would not. She built that device expecting Kaylon contact. She came prepared for Isaac, because Isaac was the mission.
Here is where it connects to Identity. Isaac's defection is the single hinge the entire Kaylon war turns on. He betrays them, he saves the Union, and the whole advance breaks. Now put yourself in a future where the Kaylon won. What is the one variable you would go back and change? Not kill Isaac, that is too blunt and they would just send another unit. You prime him. You make a small, undetectable change to his firmware years before the crisis, one that does not rewrite who he is but quietly tilts his priors, so that when he is living among biologicals and forming bonds with Claire and the boys, those bonds carry just enough extra weight to move him. The defection we see in season 2 is real. Pria is the thumb on the scale that made him able to be moved.
Now the con makes sense. A cover is not just a disguise. A good cover is a complete alternative story that gives everyone closure so they stop looking. Greedy thief tries to steal a doomed ship, crew foils her, case closed. Nobody keeps investigating a case they already solved. Nobody thinks to audit the quiet crew member who took a jolt from her device and came right back online. The con exists to end the investigation before anyone thinks to examine Isaac.
The romance is tradecraft. Getting close to Mercer buys proximity, trust, and access to command. It also lets her find the exact wound to press at the climax. The ex wife line is not an insult thrown in anger. It is a surgical strike, timed to make Mercer destroy the wormhole on emotional impulse so the choice reads as his and not hers. She needed that wormhole gone, and she needed it gone by his hand so no one would look for a hand behind it.
One more thing that looks like a plot hole but actually supports all of this. After the wormhole is destroyed, the crew still keeps their memories of her. So the show itself tells us that written state can survive the cut, even when the incursion that created it is undone. Memories persist. A firmware change is the same kind of persistent written state. She gets erased. The thing she wrote stays behind.
I will be honest about the weak spot. "Pria" aired well before the Kaylon reveal, so the writers almost certainly did not plan any of this. And by design the theory leaves no visible fingerprints, which makes it fun but also unprovable. I am fine with that. The episode left every piece sitting on the table whether they meant to or not.
The best cover story is the one that ends with everyone thanking you for leaving.