Editor's Note: The following interview contains major spoilers for the finale of Season 3 of For All Mankind.In "Stranger in a Strange Land," we once again find the world of For All Mankind being upended at the end of a season. A new addition is thrown into the group on Mars in the form of a North Korean astronaut (C.S. Lee) (who was actually the first man on Mars), Danny (Casey W. Johnson) reveals to Ed (Joel Kinnaman) that he was responsible for the drill accident, Kelly (Cynthy Wu) is jettisoned up into space so that she can give birth to her baby, and tragedy strikes at the Johnson Space Center.

We spoke with Shantel VanSanten about the devastating attack on the space center that led to Karen Baldwin's death. While the show has certainly never been cautious about killing off main characters, this death hits particularly hard after seeing Karen rise to the pinnacle of success. By the end of the season, she was not only a successful businessperson but also the CEO of Helios. In a post-mortem on that finale, we talk to VanSanten about Karen's journey, how she predicted Karen's death, filling up journals with the history of Karen between seasons, Karen and Wayne's friendship, and passing on the baton to the cast.

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COLLIDER: It's so great to speak with you, especially after watching that season. I feel like I've gone through a roller coaster of emotions!

SHANTEL VANSANTEN: More so than any other season?

Yes, especially for your character! It was a devastating moment. But first off, this season has been a huge one for Karen. For Karen, who had risen to a position of authority, what has it been like for you traveling with Karen on the journey – from when she was just the astronaut's wife, through a chaotic second season, to where we are now?

VANSANTEN: Yeah. By the way, you have to have a bit of chaos in order to evolve. You know, I think it's always easier in retrospect, now, to take a look at Karen's journey. When I was in it, I was in it. And I was trying to understand, and trying not to judge, and just be present with what was written. I remember starting off the show and thinking, "I'm so jealous," because in real life, I would go to space, I would be the first one to sign on the dotted line: Goodbye, love everybody, but I'm going and honestly not think twice. And I was so jealous of all the other girls that they got to be these badass women who were redefining feminism and standing up and changing history.

And I was a Karen before we knew what a Karen was – stuck in the mud. I, then, by the end of the season, understood the device of needing somebody like Karen, in order to show progress. I also started to understand where her resistance to change came from. It came from fear and I understand that to be the human experience. That we are all so terrified of change, and yet, besides death, it's the only inevitability in life. And so I started to love her, because I started to understand her, and I wanted to find empathy. Then we went into the second season, and I watched this evolution of her becoming a little bit more of her own woman and putting herself out there, and finding herself a little bit more because she's inspired by these women and the world changing. The bar was just an extension, in my mind, of how she cared for what was in her home on a greater scale. She was able to find the spark of business interest.

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Then this choice of [sleeping with] Danny happened and as I talked to people, it's very polarizing, but it's also just human. That doesn't mean that I'm condoning it, it doesn't mean that I don't have my own feelings about it. But I also didn't want to have my own feelings about it, because it's part of her story. It wasn't for me to judge it was for me to just be present and figure out the why, the how, the inner workings of it, and to just be truthful and honest.

This season, obviously, we get to see that inner working finally in the conversation between Karen and Jimmy. That was the catalyst for Karen to finally speak her truth, which was a lot more gray than black and white. It's a lot more confusing, and it was really difficult to love Ed. We see this season, one of my other favorite scenes, is when they're sitting in that kitchen and there's still so much love. There's loads of it until the end, like that doesn't go away because of mistakes or because they're not married. It's complicated and human and beautiful. I really commend our writers for pushing the boundaries of things that are uncomfortable to see and hear and talk and act and do. Because that's kind of the human experience.

Starting Season 3, we see a woman who's finally in a place, I believe, she always wanted to be in, but she sacrificed for other people. And while that was beautiful, it wasn't her truth that she was living in, and now, she finally is. Then even within that truth, she constantly gets challenged. Until that day comes that we all dread, and we never know. And it was heartbreaking. I would love to have seen what more Karen could have done with her life. But isn't that what death always does? It makes us wonder how we would have lived and what could have been possible. At the end of the day, our show is about loss.

It's about progress because of loss. And we all know watching this show that everyone will die because you jump ahead, and we knew signing on that eventually we would die. It doesn't make it easier. I've spent the last part of last year grieving the loss of a friend in my mind. And Karen. And the loss of the story and my friendships on the show. It's a tough one, but it's also brought an immense amount of gratitude for the lessons I've learned, the stories I was able to tell, and the family I made on that show.

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Yes, I mean, Karen is one of my favorite characters because of how complex she is. You never know what you're gonna get with her, but it always makes sense. But speaking on that finale and Karen's death – and I was sobbing at the end of that, because she had reached a summit in her life – were you given any early notice on Karen's death? Did you know at all or did you discover it at the time you were handed the script?

VANSANTEN: Absolutely not. I will sing my bosses' praises forever, not just because of the amazing work that they allowed me to dig into, but because they're so respectful, Matt [Wolpert] and Ben [Nedivi]. I oddly emailed them, in like Episode 7 – I had a really weird gut feeling, I usually do. This is just who and what I am. I have really weird instincts, and the day that I emailed them and was like, "Hey, we should chat about the rest of the season?" And I had no idea. No idea. And I got an email back the next day from Ben, and he was like, "How did you know?" He said, "We should talk. Come to the office," which usually is like, "Oh, my God, principal's office. Am I in trouble?"

I just wrote him back and I said, "I'm dying, aren't I?" And he's like, "Well, let's talk." And I said, "It's okay, we can talk. But I just want to know." And he said, "Yes, but I want you to know, it was so difficult. And it's so strange, because we were in the writers' room, and we made the decision and broke the story the day that you emailed." I mean, Joel will make fun of me forever because there's something about the soul of Karen, that started off as my grandmother, and she was and is my grandmother. My grandmother lost one of her sons at 14, there's just so many stories that are in there. And she evolved into my mom and some of her stories, and in the end, some of my stories. So, it's so personal, and it's so hard to not get lost in it.

And Joel makes fun of me for it, and that's okay because I love and will always love this character. And so often, I don't find that actors talk about the grief that comes from ending TV shows and ending four years of something I loved. I haven't watched the finale, if I'm being honest, I don't want to because then it means I'm gone. Today, I was sending voice notes [to one of the cast,] while they're doing prep for Season 4, and they're like, "You're still here." And I was like, "I know. I know I am." I don't want to think that I'm dead. I just want to think, I'm right here. I'm just like a little guardian angel. I'm still around.

All of the love and stories and memories that we have are still imparted in our friendships and in the work that we got to do together. I wish I could say that it's okay, and I'm fine and life goes on. But this one was a tough one. It was really hard and will be really hard to let go of. I don't know if I'll ever get lucky enough to have basically another soulmate of a job, which is what it felt like, and I'm okay if I never do. This got to be the thing that I loved the most, because I learned a lot. I was challenged beyond belief. And I made friends in the cast and in Karen for life.

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That's amazing. I spoke with Cynthy Wu about prepping for her character and the space between the time jumps. She was telling me that you guys had an idea that Karen and Kelly went on a mother-daughter roadtrip after the divorce, and I would have loved to see that. Were there any other scenarios that you played out in your head that took place in those in-between years? Ones that you wish you'd had the chance to explore?

VAN SANTEN: I don't think I could tell you all of them, because I have an entire journal. I have a journal that I kept between each season and that's the problem. Here's what people don't understand. I don't spend just 10 episodes and seven months shooting with Karen. I spent four years of living in Karen's skin, coming up with over 30 years of memories and stories, I literally have a journal that I think that maybe someday somebody will fucking care about. And within the journals are when she started menopause, to trips that she went on by herself, to songs she listened to on the way home from signing the divorce papers, to every single entire time jump, there is probably hundreds of pages for each 10 years, of fake memories I would come up with, in between, that would fill in the gaps and allow it to feel nuanced and have this history that we never saw.

But that happened. I think that Ed and Karen finally went on a honeymoon that they never got to have in between Season 2 and 3. I think of a lot of things. And in my own mind, they already happened. So, I always say that I would love to have seen the mother-daughter road trip. But Wayne [Lenny Jacobson] and I had many adventures and I know this. And then, in my mind, me and Lenny come up with so many fun scenarios of what they did together. Like, "Okay, we went did like ayahuasca for sure." He's somebody who really challenged her to push the boundaries of what she was comfortable with, to find herself in that friendship. It was such a pivotal part of her story that I would want to explore forever, just because of how polar opposite they are.

So there are so many things that I would love to have seen for Karen. But, you know, I got to live them in my imagination, and I got to breathe life into them and bring the nuances to the scenes. And so, in a way, they did exist, because they were behind every word that she said.

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God, I mean, I would totally sign on for a miniseries of a Karen and Wayne tv show. Some kind of HGTV thing where they cook in one episode, do yoga on another, talk about life.

VANSANTEN: Yes! I mean we always say that he had a VW van, and they would just go and set up shop somewhere. And I loved that chapter and friendship in her life. I love that we got to see a little bit of it this season. Our show moves so quick, but we remember that it's still there. Our writers do a really good job of hinting at those things so that people remember that that's still a part of our life, even if we don't get to see it on screen.

Yeah, definitely. I was so excited to see Wayne and Karen back together again.

VANSANTEN: That was one of my other favorite things when I read it, and when we got to see Karen laugh. I remember thinking, "What does Karen's laugh sound like?" Because we never get to hear her laugh, like just be high as a kite, laughing her butt off. It'd be so much fun.

I would definitely enjoy an afternoon making goo balls and getting high with Wayne and Karen!

VANSANTEN: In my mind, by the way, her life ended up — she had enough money that she could just go on a cooking channel, and her and Wayne would cook the most ridiculous things with weed in them, because it's now legal, and that's what they did.

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Image via Apple TV+

I love that future for her. Thank you so much for speaking with me. Honestly, this has been one of the best seasons so far. I so enjoyed watching it and watching Karen's journey. I'm devastated we're at the end.

VANSANTEN: The thing is that I have full heart and faith in who we get to pass the baton onto. Sonya [Walger] and I, who plays Molly, had this conversation. It's there, and we get to watch it grow now. We got to be a part of it. It feels like I'm sure what having a child feels like. I wouldn't know. But, you know, you get to be around and help shape and mold and create memories. Then you have to just let it go. I'm going to be just like you, a cheerleader of the show for as many seasons as it goes, and just championing it through all of time and space. And I feel lucky for the chapters that I got to be a part of.

Well, they were certainly some of the best chapters. So, thank you so much.

VANSANTEN: Thank you, and thanks for watching the show and just tell everybody to keep watching, because I'll be there doing that.