The fifth season of Girls has been one of the best of the series, with each of the four main characters on her own journey. On last night’s episode Marnie (Allison Williams) got an adventure all of her own. In one action-packed day she gets in a fight with her ludicrously narcissistic husband Desi (Ebon Moss-Bachrach), runs into her ex Charlie (Christopher Abbott), gets propositioned as a hooker, nearly drowns in Central Park, gets mugged in an outer borough, and does the world’s most horrific walk of shame only to tell Desi that she is ending their marriage. Williams gave a bravura performance in a season that has been full of them.

Today, she spoke to Vulture about just how gross that red dress was, why filming underwater is horrible, and what it is about Marnie that makes people think she’s the worst.

My biggest question for you is, how gross was the Central Park pond?
Here’s a little secret: We shot the pond sequence in a different pond in Staten Island and then we shot the underwater stuff in a swimming pool in Manhattan.

So you didn’t have to get into the Central Park pond at all?
No, and I didn’t realize that until about a week before production and I had spent so much time thinking about it. I’m not a germaphobe and the walking-barefoot thing didn’t bother me that much, but I spent a lot of time thinking, They wouldn’t put me in a pond where I can get any real sickness. Kind of talking myself down in advance. Then when I heard the production plan I was just like, Okay.

I was just relieved that we were breaking it up into two pieces because being that cold and wet for that long was going to be difficult. And it was hard on both sides of the stunt — the underwater stuff was one of the hardest things I’ve ever had to do. I was not expecting that. I thought it would be like a pool party with your crew.

What was so hard about it?
It was swimming in shoes and a dress, which is harder than it looks, and trying to emote underwater with your eyes open. You’re trying to control the air bubbles so you don’t look like you have boogers the whole time.

Did you have to stand on the bottom of the Staten Island pond?
No, that was the swimming pool. They brought the boat into the swimming pool. It’s all effects.

Look at you, so high-tech on Girls. It’s like Game of Thrones.
[Laughs.] Basically there is no difference between Girls and Game of Thrones. It’s time everyone noticed.

The whole episode is about Marnie coming to a realization and making a change in her life. What do you think she learned?
In the beginning we see someone who has reached her limit in her ability to be pleasant, and she is doing her best to deal with all that is Desi. We see someone who is completely frayed and cannot cope anymore, so she extricates herself, which is the right thing to do in that situation.

At the moment she runs into Charlie, her instinct to walk away from him is just like, Are you kidding me? Not now. Of all the moments, why can’t it be, like, when I’m dressed up to go to some event? Why is it when I’m in sweatpants and high-tops and some weird shirt and my hair is in a bun? She would rather run into him when she’s making out with Desi and they’re on cloud nine together.

From the moment she decides to go wherever Charlie wants to take her, she turns off the part of her that is so fundamental, which is to evaluate and assess everything that is happening to her at any given moment. That often comes across as being judgmental or seeming hypercritical, but in reality it is someone who has never had any mooring in her life due to a complete lack of parenting trying to keep herself grounded. She is just trying to be present.

Ironically, it’s the one time in the series where she really needed her instincts and she really needed that actual part of Marnie where she is judging, because if she had that turned on she would have noticed Charlie’s erratic behavior early on, she would have been able to call bullshit on his news about his dad. When walking into that apartment, she should have turned around and been like, Listen, the Charlie that I know had that incredibly well-designed thing out of a catalogue. Something is definitely wrong, and then left.

That she was trying so hard not to be herself in that moment is leading up to that moment where she can see things through her own eyes again. But it’s what happens to her in those intervening moments that allows her to come to an uncomfortable realization, during her walk home, about her life and the decisions she needs to make.

Lena wrote a total masterpiece.

At one point in Charlie’s apartment she says, “I don’t need to change anyone anymore.” Do you think that’s true?
I think that, in that moment, she is high off the new version of herself where she can just accept people as they are. She knows that is the biggest criticism she gets from people is that she’s so judgmental but is afraid to examine herself. It’s all the things that Ray said to her that time she went to his apartment seeking constructive criticism.

We were trying to figure out how to get her to find the paraphernalia; maybe it was [director] Richard Shepard’s idea or maybe it was mine to have her sleep-deprived and not thinking and just start straightening up his room. I loved that because she comes in and says something positive about the shower, which is something that is so not Marnie, and with love she’s straightening the room and looking at that red dress and thinking, Is this my life now? Are we about to go to a little town and open a general store, is this real? Then she’s snapped out of it by the reality of who Charlie has become.

Do you think she really knows as little about the world as Desi thinks she does?
I don’t. I think Desi in that conversation in the stairwell cycles through all of his tactics. He starts with “You’re going to get murdered,” then he just cries, and earlier he tried to use logic and anger. He’s trying to use any means necessary to get at Marnie. The only way for her to deal with him is just sort of accept the idea of her murder with whimsy and openness, which is just like, Okay, maybe that’s what happens. I don’t think he gives her enough credit. He should at least give her credit for what she knows she doesn’t know. In that Rumsfeldian way, there are known unknowns. There aren’t those major blind spots we’ve seen in her before. She’s self-critical above all else. She’s really ready to be on her own and realizes that’s what she needs. I really loved that. She has more fight than Desi gives her credit for.

Desi not knowing her in that moment is so important because she’s like You’re a total fucking stranger and I married you. You don’t even like me or respect me. Given her incredible lack of parenting — a dad who didn’t come to the wedding and a mother that makes it all about her — Charlie was that family for her, and now that has been taken away and she knows she has to be that for herself. She has tried once more to have someone do that for her, but she’s realized that she’s nothing if she’s not grounded on her own.

Is this the end of Marnie being the worst? Because Marnie was always a little bit of the worst.
It’s so funny you say that. So many people have said that to me over the years. When you’ve spent so much time with someone over the past six years you end up aligning yourself with them, and I’ve put so much of myself into her. But I can also see her with some remove, and I can watch the show and see how she comes off. My instinct was always to ask Lena, “When is she going to fix everything and be okay?” I would always say that my one wish for this season is an act of kindness and selflessness from Marnie.

I hope after seeing last night’s episode people will understand those qualities in her that make people think she is the worst. Her desire to sum everything up and assess everything as she goes comes from a place of having no moorings in her life. Even when she goes to stay with her mom after her breakup with Charlie, it is not a great situation. She might as well go live in a shelter somewhere. Her mother provides little to no assistance in helping Marnie; it’s all about her being single and leaving Marnie’s dad. What we see is someone trying to make a nest for herself to feel stable. Given her friend group, given her age group, given everything, that is going to be really tough for her to do. What people find annoying about her comes from that effort.

I hope after Sunday night’s episode that will all be clear to them. Her survival mechanism is to make sense of everything in the moment, and her inability to be present in certain moments is because of that. That is always what has kept her safe. Yes, that means she’s rude and can be selfish and has dated the wrong people, but it’s kept her from getting murdered. And it keeps her from being murdered at the last second in this episode. Her instinct is not to believe that he’s diabetic. You don’t need that telltale rubber line if you’re diabetic. It got her out of there.

I hope people emerge not just with a fondness for Marnie, but also an understanding of what makes her so infuriating sometimes. That’s my very long-winded answer.

That’s a fair answer.
I was nervous because I know how people feel about her; they’re very honest with me about her, and I can see with my own eyes how she acts. I’m not immune to her shortcomings. Going into this episode, I was so proud of it and I was terrified that people wouldn’t be able to be swept up in it. But Lena’s amazing writing and Richard Shepard’s incredibly artful direction make it impossible not to get swept up. It felt like you’re watching a short film. That’s what I said to Lena the first time I saw it.

I think the audience wants the same thing you want, which is for Marnie to get it. She starts this adventure and she has that conversation with the woman in the thrift store and it’s like, “Jesus Christ, Marnie. Not again!” But by the end of it, she gets home and you think she’s a different person.
That was the gift of the episode. Reading it for the first time was the most exhilarating thing. I was crying and sweating and shaking. I was so excited to shoot it. There were so many things I wanted to make clear in every moment, and I wanted to know how it would be shot so I could know how subtle I could be. I was so excited for this challenge — portraying Marnie in all of these moments. I could not wait for that.

To react to getting mugged by saying she didn’t know that happens anymore is so classically Marnie and naïve, but it is honest. She is saying that she had forgotten that this was something that could happen to her in the city. Then there is an eyes-wide-open aspect of her at the end that I wanted to show. I didn’t want her to be a sobbing mess because that happened somewhere around the bridge on the way home. By the time we see her, all she can muster is that last conversation with Desi, yet when she finally crawls into bed with Hannah and Fran she is not immediately passing out — she is deep in thought trying to process everything that’s happened. I love how the close-up of her face at the end of the episode mirrors the one at the beginning of the episode, and they’re similar expressions, but they feel entirely different.

I just can’t believe Hannah and Fran let someone crawl into bed and didn’t do anything.
It just feels like their roots. Hannah and Marnie wake up in bed together in the very first episode of the first season. It’s that real love where Hannah looks over and sees Marnie and knows she needs to be there and doesn’t ask any questions. It doesn’t matter what she’s been through. I think if Hannah crawled into bed with Marnie she would react in the same way. She could have gone anywhere at the end of the episode, and there were some different endings they played around with, but this felt the most interesting, and the fact that she wears the dress and just puts a sweatshirt over it is so telling to me. That dress that is so wet and disgusting. There is something about that night that she wants to keep with her until she wakes up in the morning.

Were you so sick of that dress?
I was so sick of that dress. There were a couple of different versions of it because there was one that was really dirty, one that was just kind of dirty, and a few wet ones. I never would have worn that dress in real life because my sternum kind of protrudes in this weird way, so I always avoid wearing something low-cut. When I read the description and it said the slit is high and the cut is low, I thought, If Marnie is going to be so far out of her comfort zone then I will, too. I was watching Vinyl and Olivia Wilde wore that red dress and I thought, That is who should be wearing this dress. I have no business wearing this dress.

But it was helpful because I was cold all the time, I was uncomfortable all the time, I was self-conscious, and that was really helpful because that made it easy for me to focus on the more nuanced aspects of her emotional state because I knew I didn’t look like a million bucks in it.

What was it like filming with Christopher Abbott again?
It was so meta in a million ways. First of all, I hadn’t talked to him since he left the show, and I had a lot of the same questions that Marnie did, but I didn’t ask him because I wanted to leave that in the show. Also, like Marnie it came back to me immediately, our dynamic. It took no work to find that Marnie-Charlie vibe again, like it did in the show. It felt really comfortable but foreign because it had been so many years. I had gotten used to doing sex scenes with Desi, and since then, it was weird to be doing a sex scene again with the person who I did a sex scene with for the first time. He was so fantastic in the episode and just watching it was great to see them onscreen together.

Was it weird on set at all, since he said some harsh things about the show after he left?
It’s hard to describe. I left all of that alone. I still haven’t asked why he left. I know a little bit of what he’s been up to, but I didn’t delve into it. I wanted to respect whatever the decision was to leave the show. Obviously, I would think that you would have to be in a very different place than I am to leave, because I think it’s the greatest gift ever and everything good that has happened to me professionally I have to thank the Girls family of Jenni [Konner, executive producer], Lena, and Judd [Apatow, executive producer]. You’re going to be given gifts like this episode or the first episode of the season. I can’t imagine leaving it of my own volition. I just imagined how uncomfortable it must have been for him coming back to this show that he used to work on and be able to focus and do his job, so I tried to respect that.

We know that Girls is coming to an end after next season. Where would you like to see Marnie end up?
I don’t want to reveal that because I’ve talked too much to Lena about it and I don’t know that I can un-know everything I’m not supposed to know. What I hope is that the lessons she learned in Sunday’s episode, even if they’re not right on the surface like they were, that they leave a lasting impression on her and that she realizes so much of what she has been looking for externally needs to come from within. I think she already has learned that.

Allison Williams of Girls on Her Big Episode