This Is Us : Milo Ventimiglia Unpacks the Moment Jack 'Crossed a Line' with Rebecca

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This Is Us took fans on a ride down memory lane.

Tuesday's episode, titled "The Ride," saw four sets of parents — Jack (Milo Ventimiglia) and Rebecca (Mandy Moore), Kevin (Justin Hartley) and Madison (Caitlin Thompson), Kate (Chrissy Metz) and Toby (Chris Sullivan) as well as Randall (Sterling K. Brown) and Beth (Susan Kelechi Watson) — on a series of car rides home from the hospital following the births of their babies.

After the Big Three's birth on August 31, 1980, Jack and Rebecca's first ride in the station wagon with their newborns was a bit rocky. An impatient driver cut them off and the new dad almost got into a heated confrontation with the driver at the gas station, where Jack bought and downed a mini bottle of whiskey due to feeling overwhelmed and losing control.

New parent jitters were also immediate in the present-day when Kevin, who was running on little sleep and was followed by a paparazzo, brought his twins, Nicky and Franny, home with wife-to-be Madison, who appeared to be taking parenthood in stride. On the other side of town, Kate and a newly laid-off Toby, with their new baby girl Hailey, said goodbye to Ellie (Annie Funke), who agreed to an open adoption but was having doubts about staying in touch. Meanwhile, Kate and Kevin's parenting experiences were juxtaposed to the past when Randall, who always wanted to expand his own family tree, and Beth welcomed their second daughter Annie.

Then, at the end of the episode, viewers were treated to another flashforward to the future at Kevin's house, where adult Annie and a pregnant Deja joined the rest of their family, who had gathered to be with an ailing Rebecca. And the cliffhanger: another car arrived at the house, possibly another family member (Kate?!).

While fans await more answers, Ventimiglia breaks down how Jack reacted "under a lot of pressure" and tells PEOPLE about his personal reactions to the emotional scenes his character isn't physically in, but is posthumously referenced to.

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PEOPLE: What was Jack's mentality right after the births of the Big Three?

MILO VENTIMIGLIA: Stress. Just absolute pure stress and worry and everything I imagine a parent to be dealing with having one child — now you're responsible for three. Overwhelming, all-consuming fear. But knowing who Jack is, he's got to keep it together. He is the mask of strength. He's always the one that's got the plan and he's in control and he knows what's going on. He rarely ever loses it. But I think this one definitely throws him in a way that he's not comfortable with. But also, Jack being who Jack is, this is all he's ever wanted. So, I think there is the overwhelming sensation of what's going on and this papa bear protection just instinctually happens as I understand it.

Men become fathers the day their kids are born. Women become mothers the second they conceive. It's just a different clock as I'm told by all my friends that have kids or my parents. So I think the day of the birth of the kids, to have experienced the loss of a child and the hope of adopting another, and then the responsibility of bringing them home — man, Jack's under a lot of pressure. And he's got a lot of expected joy because all he's ever wanted was a family, but the pressure is just … this episode we definitely explore that.

We've seen Jack's childhood, we've seen the relationship he has with his own father, Stanley, and in recent episodes, we saw Jack trying not to be like his dad. But alcoholism isn't a defining trait for Jack, unlike Stanley. Can you break down the perfection Jack struggles to maintain?

Jack is a man of a particular era. I watched my dad when I was growing up and I'm trying to really understand the weight of what Jack carried, having been in the war when he was a young man, coming from a working-class family and trying to provide better for his wife and having three kids.

Jack downing a little bottle of booze that he picks up at a gas station, maybe to knock the edge off, I mean, is that the beginning of where Jack's real alcoholism starts? Under pressure? Or is it just something that Jack can just handle? Knowing where Jack goes, I think the end of season 1 and into season 2, he's dealing with AA and admitting to his daughter and his kids that he has a drinking problem. I think this is just the early set of that. We've touched on that with Jack before — when he has a couple too many gin and tonics when he's on the golf course with Rebecca's father and he almost knocks Rebecca's father out when he makes a comment about him not being good enough for his daughter. So, Jack's complexity, and, I guess, dance with alcohol, is a tough one. It's definitely one that when he's younger he thought he could handle. Every young man thinks he can handle everything. It's not until you're old you realize, "Hey, I'm not equipped to deal with this." It took him into his 50s before he really addressed it.

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In the last two episodes, we've seen the SuperDad part of Jack and his hero moments. Is this episode showing more of the human side of Jack?

Definitely the human side. Even superheroes have their moments and have their pressure where they hit a breaking point. The good thing about Jack is, he knows when he's crossed a line. And what's nice about this episode is, I don't want to say reliance on his wife, but the trust in his wife. He crosses a line and ultimately he ends up talking to her about things and having her take the reins in that moment because he knows he can't. Even though she's just given birth to two babies, lost a baby, found out her husband wants to adopt a child and they're on their way home for the first time, yeah, I think this was one of those trying days for Jack and Rebecca. Totally.

This episode is seen through the lens of all the characters coming home with their babies. Why do you think the story was put together like that?

It's the commonality. Being a new parent, it's got to be scary. And it's not just scary for Jack and Rebecca — it's scary for Kate and Toby in a way, because they've trusted that the woman that they're adopting from is going to go through with it. Kevin and Madison, it hasn't been easy for them and their struggles. Two complete strangers ultimately making a huge life decision to go through this and have twins. Kevin was not around because he's doing a movie. Things are against them.

And then there's old steadfast, Randall and Beth. They have their own experiences and I think we've seen a lot of their parenting and the product of how Randall was raised, and what he's learned of his own heritage and culture of himself that wasn't learned through experience with his mom and dad, Jack and Rebecca. I like the commonality. It's everything Pearson. I thought it was a really nice nod to the shared experiences that we can all have.

RELATED: This Is Us' Sterling K. Brown Teases Randall and Kevin's 'Conversation They've Been Looking to Have'

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About the dream sequence with Jack meeting Kevin's baby twins: PEOPLE previously spoke with Justin Hartley and he said, "The circumstance of Kevin losing his father too early is heartbreaking. ... Naming the baby after [Jack's brother] Nicky, but not being able to share that with his father is heartbreaking."

No matter what, Jack is always present because the adult kids always talk about Jack. He's still there because they're talking about him, they're taking what they have known of their father and they're applying it to their own lives. Whether they're dedicating it to their father by Kate naming her son, Jack, or Kevin naming his son after his uncle, a familial thing, or it's just inherent because it's who they are.

Jack is always involved. He's always involved with their lives. I think the interesting thing is, for me just watching the show — because I'm a fan as well as being a part of it — when we jumped even more in the future and Kate's son, Jack, was an adult with his sister, they're talking and I'm like, "Wow, these guys, they really have no idea. They have no idea about Jack." And then it starts to teeter on, or there's something a little lost and a little missing. [Kate's son] carries the name, but he never knew Jack. I mean, my grandparents aren't around anymore, but I would kill to have another hour with them just to have a conversation, just to hang out. Just to hear something more, or a day, or a year, or a month, or anything. But that's because I had the experience with them. Whereas, baby Jack never even knew Jack.

RELATED: This Is Us' Justin Hartley Discusses Jack's Legacy and Kevin Making It to Delivery Day in Time

As a new dad, Kevin is still chasing the ghost of Jack. He can't stop comparing himself to Jack, who says, "Do [the twins] a favor: Stop trying to live up to me. I was terrified of being like my dad, and you're terrified of not being like yours."

Just think about the last moment they all had together. It was an argument in the kitchen, and Kevin was being a jerk to his mom and his dad and he stormed out of the house. And then he wasn't around when the house burned down because he was out with Sophie and he never saw the note from his dad because that burned up in the fire. The only person who knew about that note existing was Jack. So there's always going to be, for Kevin, chasing his father down for what he never got, which was some moment of closure or goodbye. That's got to chew someone up. It's got to chew them up. Jack was taken away from his kids, taken away from his wife. They all thought he was okay, but he wasn't. I think Kevin's always going to have to carry that and he's going to have to find it within himself, in one way or another, the strength to say, "Hey, I don't need to live up to my dad. I learned everything I could from him. And I need to honor what I did learn and become my own man."

In a past episode, we saw a more mature parent/child dynamic between Jack and young Kevin. Will there be more instances where Jack won't necessarily baby his kids?

I literally have one in mind and it's a really beautiful moment between Jack and his kids, but I won't spoil that one for you. But yes, the answer is yes.

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"He was punctual and arrived right on his due date, much to the delight of his parents," she says

And there's still a lot to explore about Jack's life that audiences haven't seen yet, particularly the early years of Rebecca and Jack's romance. What can you tease about how Jack will get acceptance, or if there is even acceptance, from Rebecca's father Dave, played by Tim Matheson.

We lost Tim Matheson to another production and we couldn't fully explore that dynamic. So hopefully we'll be able to get that back sometime this year and next year. But, I mean, we've seen Jack as a father, we've seen Jack as a husband, we've seen Jack through his own alcoholism, through war, through his death. I got to believe that the writers are coming up with plenty more that we haven't thought about for Jack. And I say that in my own interest of job, but also because I think Jack has always been a character that a lot of people can see themselves in and that's what's made him accessible. I don't think relatable, just accessible.

In life, I get a lot of people talking to me about their lives and being fathers and how they approach it. They look at Jack's point of view and how he approaches it, it just feels the same. It feels accessible. And that's what I hear the most. I just think that's wonderful to play a character that can inspire a man to be a better father, a better husband, a better person, a better friend, or a parent, or a mother, or a son, or a brother. It's nice to let people know that some goodness is going to grow from it.

This season is addressing COVID and the racial reckoning in the present-day timeline, so you've taken more of a supportive role acting-wise and Jack is servicing other characters, especially through memories. What would you tell the fans who may feel your absence on screen?

I am the wrong man to ask that question. I really truly am. My duty is to the words that are written, no matter if they're serving another character's story or it's something that is purely discovery of Jack. I'm at the service of the word on the page and that's really it. I think there's still more to learn about Jack and even if he is a little secondary, I still don't think that takes away from who Jack is and Jack's service to the family — Jack's service to himself even. I'm sure I'll probably be directing again and hopefully, people can see my handprints all over it.

This Is Us airs Tuesdays (9 p.m. ET) on NBC.