Do you remember that episode of ‘Seinfeld’ where George complained about worlds colliding? ‘Fringe’ is a lot like that now, but literally. Worlds are colliding. If somebody doesn’t do something about this, it’s all going to blow up.

With last week’s episode, called ‘Entrada’, the jig is finally up for the evil Fauxilivia. Peter figures out the secret of her identity, and she’s smart enough to know that he’s on to her. She gets the drop on Peter and forces him to inject himself with a paralytic compound that will keep him frozen for a little while so that she can escape, but doesn’t kill him. Probably because she actually has some feelings for him.

Stupidly, Fauxlivia grabs the wrong laptop on her way out, which allows Peter (a few hours later) to track her to the typewriter shop in the Bronx, and from there to Penn Station. There, she meets up with a shapeshifter whose job is to help her get back to her own universe. The shapeshifter takes the form of an innocent bystander so that Fauxlivia can pretend to take him (now her) hostage. This seems kind of pointless. Given that nobody else has seen the shapeshifter in his previous body, what’s the point of taking another one? Why can’t Fauxlivia just pretend to take him hostage as is? Anyway, Peter is clever enough to figure out the ruse and shoots the woman in the head… right in front of the victim’s daughter. Nice job. Fauxlivia is then taken into custody.

Meanwhile, in the alternate universe, Walternate is working on a retrieval plan for Fauxlivia that entails swapping her body for another of equal mass. The real Olivia would seem to fit nicely, but first he’s going to slice out her brain and some other major organs for study. That shouldn’t be a problem so long as he replaces them with something of equivalent mass.

Before that can happen, alternate Broyles helps Olivia escape. He’s developed sympathy for her, and hopes that she can prevent the war between universes that Walternate is planning. First, they try to go to the sensory deprivation tank in Walternate’s lab, but it’s been emptied and dismantled. Alt-Broyles has to help Olivia get off Liberty Island entirely and get to the abandoned lab in Harvard. Olivia figures that Walternate would have kept a sensory deprivation tank there just as Walter does, because they share the same DNA and must think alike. Or something.

The rules for traveling between universes just keep getting more arbitrary with each episode. All the stuff in the last few episodes about Olivia needing sensory deprivation has come from out of nowhere, and has nothing to do with any of the other methods for crossing over that we’ve previously seen. Also, when she finally makes it to the lab in Harvard, she jumps in the tank just as bad guys storm the lab. She can very clearly hear them tromping around and yelling and shooting. There’s no actual sensory deprivation at all. Yet she immediately crosses back to our universe. If that’s all it takes, she might as well have just laid down in a random corner somewhere and closed her eyes.

And why is it that when Olivia crosses back, she doesn’t need to “swap” with anything? She just crawls right out of the tank in Walter’s lab in front of Astrid. Then she collapses, but I’m sure she’ll be fine.

While Walter and Peter are still at Penn Station wrapping things up there, Fauxlivia vanishes from the paddy wagon they’d kept her locked in. Walternate managed to pull her back. The item that he swapped her with is alternate Broyles’ corpse, minus a few appendages to even out the mass ratio. Regular Broyles is pretty horrified when he sees that.

The episode ends with Peter at Olivia’s bedside, feeling guilty. It undoubtedly has occurred to him that he’s only ever had sex with (and, more importantly, formed a serious emotional bond with) her evil doppelganger. This seems like the sort of thing that will be a setback in their relationship.

In a lot of ways, ‘Entrada’ feels like a finale (or at least a “fall finale”) episode. It wraps up the whole body-double storyline pretty conclusively. So I’m surprised to see another new episode scheduled for this week.