Ted Danson and D’Arcy Carden in The Good Place. Photo: Colleen Hayes/NBC

Proving it is every bit worthy of its fourth-season renewal, NBC’s The Good Place delivered one forking awesome midseason finale on Thursday night that involved not just one Janet (D’Arcy Carden), but many, many Janets. After an epic bar fight in the last episode, the know-it-all information vessel decides to save Eleanor, Tahani, Chidi, and Jason from the onslaught of Bad Place demons by taking them into her mysterious void. Of course, there’s a twist once they get there: The void makes all four humans look and sound exactly like Janet — but without her cool summoning powers and emotional control, since messing with those will blow their cover. (Spoiler: They totally blow their cover.)

So, how exactly did The Good Place pull off such a complicated episode? Earlier this week, series creator Michael Schur, Carden, and episode writers Dylan Morgan and Josh Siegal told Vulture how “Janet(s)” came to be.

“Janet(s)” has been in the works for awhile

Schur says the idea of multiple Janets emerged back in the second season, and early on they figured out the blueprint to get to Janet’s void: “Out of desperation, fleeing demons, Earth is compromised, Bad Place is comprised, there’s nowhere else to go.” At one point, they also considered limiting this story to the episode’s first act like the Groundhog Day-style storyline in season two’s “Dance, Dance Resolution.”

But this scenario had to be more than just a gimmick. After talking to Todd May, one of the show’s two philosophical advisors, about the works of John Locke, David Hume, and Derek Parfit, Schur says they had the idea that Eleanor (Kristen Bell) would begin to question her sense of self — and that would be “the thing that threatened to have everything blow up.” “The reason to do this isn’t to have D’Arcy run around and goof off as her cast mates,” Schur says. “The reason to do it [is Eleanor’s] literally asking herself Who am I? What version of me am I right now? And this is something philosophers talk about — I think.”

Plus, Schur says, “We want to internally make sure we understand [these philosophical theories] at a deeper level, so we’re not just literally looking it up on Wikipedia and cutting and pasting the first line.”

How much studying up on the other casts’ mannerisms did Carden do? A lot.

To help Carden nail her impression of each Good Place character, her co-stars recorded video footage of how they’d play the scenes, wearing the costumes that Janet wore in the episode. (But sadly, they did not wear Janet’s uniforms.)

Carden says she also recorded audio of the episode’s table read where everyone played their original parts. “There was one day where I was listening to it cranked up in my car, driving down Sunset and I see Will Harper [who plays Chidi] walking on the street,” she recalls. “I pull over and just roll down my window and just blast it. It was his voice. And he went, Oh no! You’re losing your mind!”

D’Arcy Carden in The Good Place. Photo: Colleen Hayes/NBC

Still, it wasn’t simple for Carden to imitate her co-workers. “It’s not necessarily hard to play five different characters, but it is hard to play five really well-established characters,” she says. “We didn’t want it to be like SNL sketch characters — we didn’t want to do over the top — so then it was a really fine line between not doing them enough so that we could tell who each one was and doing it too much.”

Among the quartet, Carden says Manny Jacinto’s Jason and Jameela Jamil’s Tahani were easiest to impersonate because they have specific characteristics. But Eleanor was the hardest because Bell’s take on the character is “just so subtle.” Still, Schur says Carden nailed it by aping small details like putting her hands in her back pockets (“which is classic Kristen Bell”) and occasionally slipping into the star’s native Michigan accent.

The other actors were also on stand-by in case Carden got stuck on a particular mannerism. William Jackson Harper typed out his lines for Carden in the way that he memorizes them, and Jacinto emailed her with something that inspires him when he’s playing Jason. (She wouldn’t divulge what that something was, but please let it be a dance crew holding Molotov cocktails.) Ted Danson came in to help out too, but didn’t stick around: “Ted did a day of acting with a bunch of poles and he was like, No, no, no, this is not for me. I’m going to leave now,” Carden jokes.

They had to film with multiple Janet stand-ins

According to Schur, a number of “D’Arcy height-ed stand-ins” were employed to make sure that everything tracked properly on camera. “One of the most disorienting things was going down into that room and seeing five people [D’Arcy’s] height with identical wigs on,” he said. (Carden adds that “we even had almost a diorama [or] dollhouse version of us.”)

The scenes themselves were carefully scripted and blocked to ensure that all of the doubles matched. Though actors don’t often improvise on The Good Place, Carden says, “This particular episode was super-scripted. Every bit of it was, Move on this line and turn your head on this one.”

Kirston Mann, the show’s costume designer, also had to find exact costume matches for Carden and all the actors she was doubling. It got so complicated that Carden asked for a full-length mirror just so she could take a final look at who she was portraying before she went on stage.

Behind the scenes of "Janet(s)". Michael Schur. Behind the scenes of "Janet(s)". Michael Schur.

How was the Janet kissing scene filmed?

“There was a long pole with a literal pair of lips on it,” Carden says. “Like plastic lips, but it was exactly at my lip height. It was on, like, a Lazy Susan that was controlled by some dude.” And yes, it was as tricky as it sounds. “I had to sort of hug air and kiss these lips and then we would start spinning, but I couldn’t smile or laugh,” she adds. “The kissing was one of the funniest, wildest parts because I had to kiss Kristen [Bell], but it had to match exactly the head tilt and every inch of us had to match.”

The introduction of Neutral Janet

As if Carden didn’t have enough on her plate, the writers also gave her a whole new character to play: Neutral Janet, who is neither naughty nor nice and is just kind of dead inside. “I sent [Schur] a text as I was working on it like, This is like DMV Janet, right?,” Carden says. “And that was exactly it. It was just somebody that’s like they do this all day, everyday. They’re not interested in being friendly. They just get the job done.”

Cher’s “Believe” was always gonna be the song that played in Janet’s mouth at the accounting office

“I actually also recorded D’Arcy singing it and then Auto-Tuned it,” Schur says. “And that, weirdly, was less able to be cleared because they were more willing to use it if it were the original track.”

As for the accounting office itself, it’s been referenced several times as the place where beings add and deduct Good Place worthiness points, but this is the first time it’s actually seen on screen. Given the show’s love of hidden jokes, it’s no surprise that the each desk in the office had also gets a unique nameplate, like “Songs with Specific Dance Instructions,” “Vape Tricks,” “Borrowing Money” and “Celebrity Impressions (Borat).” According to Morgan, there was also “a whole cubicle devoted to Jennifer Garner.”

That reference to The Office almost didn’t happen

Stephen Merchant, who co-created the British version of The Office, guest stars as the accounting head in “Janet(s).” His drink mug reads “Existence’s Best Boss.” It’s a nod to Michael Scott’s beloved mug from the American version of that show, on which Schur wrote and acted. However, Merchant held the mug wrong during filming and Schur had to ask VFX producer David Niednagel to digitally adjust the print so viewers could see it.

What’s next for Team Cockroach?

That kiss between Chidi and Eleanor didn’t just save their world from crumbling, it was also a big step for the decision-weary philosophy professor. “For awhile, we’ve been trying to think, What is the thing that would make Chidi get over his internal essential Chidiness when it comes to romance?” Schur says. “When we figured this out, we were like, Oh, yeah, this is the thing. He’s going to worry about a lot of things, but he’s not going to worry about her, or how he feels about her, or how she feels.” (A warning if you’re not a fan of love stories: “Picking up almost immediately in the next episode, it’s pretty gooey,” says Schur.)

Meanwhile, we’re left to wonder if Tahani will confront Janet about her feelings for our favorite Jacksonville Jaguars fan. “A lot of that stuff gets dealt with very quickly, in various ways,” Schur promises. He also says that, in the coming episodes, Michael will make use of his proof that the system to get into the real Good Place is rigged.

Are Janet’s powers going to change?

Schur reminds that Janet’s ability to understand human beings has continued to grow since the pilot. For now, he teases, “If the way to really have empathy for people is to walk a mile in their shoes, she did the inverse of that: a bunch of people walked in her body for a decent amount of time. That is another contributing factor to her evolution.”

It’s sure to set her ever farther apart from the other Janets, if you listen to Schur’s quick lesson in Janetology. “Janets are not the Borg,” he says. “They’re not psychically connected to each other. They can’t look through each others’ minds. They’re all individual entities. It’s not like if you upload something into Janet’s not-brain, it will be uploaded into all of the Janets’ not-brains.”

Why has the Good Place been broken for so long?

“The question of why no one has gotten in [the Good Place] in 521 years will be answered in the next episode,” Schur says. But like so many other small details on the show, that specific length of time wasn’t an arbitrary choice. “We sort of figured once the world was closed as a loop — once exploration moved from Western Europe and had moved across the ocean — after that moment it was essentially impossible for anyone would get in by the criteria we set up,” Schur explains. Sorry, Abraham Lincoln and Harriet Tubman.