Johnson also opened up about joining the celebrated adaptation as a fan of the game.
Spoiler alert! Warning: spoilers ahead for The Last of Us episode 5, titled "Endure and Survive." Do not proceed if you haven't watched!
Every episode of The Last of Us seems to come with a guarantee: You're going to meet an amazing new character, and, an hour later, be emotionally devastated about them.
Such is the case with episode 5 -- which was released two days early due to Super Bowl Sunday -- which opens with the introduction of Henry (Lamar Johnson) and Sam (Keivonn Montreal Woodard), a pair of brothers who ambushed Joel (Pedro Pascal) and Ellie (Bella Ramsey) at the end of last week's episode.
"Our relationships, I would like to say, are very much mirrored," Johnson told ET's Ash Crossan during an interview for The Last of Pods, an ET and Comicbook crossover podcast. "Henry and Joel are very much the same, and Sam and Ellie are very much the same, and those relationships are quite mirrored."
The foursome end up forming a bond and making plans to travel to Wyoming, however, the episode comes to a tragic end when Sam reveals to Ellie that he's been infected and is about to turn. Not telling his brother or Joel leads to chaotic consequences when Henry wakes up in the middle of the night to find his turned brother attacking Ellie and has to make the decision to kill him.
"It's a very sad scene," Johnson reflected. "I'm really grateful for the opportunity to be able to step into that space and interpret it in my own way. I also didn't wanna create a carbon copy from the game. I did want to honor his performance, because it was beautiful and it affected me when I played the game. But I did want to add my own self and my own instincts to that scene as well."
Johnson praised the show's makeup and prosthetic departments for creating the horrifying visuals for him to react to, but the real tragedy of the moment is compounded by the small glimpse of hope just moments earlier.
"Henry goes to bed joyful, with hope, because Joel had just said, 'Hey, what are you guys doing? We're going to Wyoming. Do you want to come?' 'Yeah, sure. It'll be great for Sam to have a friend.' You know?" he recalled. "There's hope and there's joy in that moment as I go to bed… and then to wake up and see Ellie screaming and Sam trying to [attack her], it's really just confusion."
Noting that Henry isn't aware of Ellie's immunity, Johnson said his character initially goes into protector mode, trying to keep the ruthless Joel away from his brother, but then makes a life-or-death decision -- and it's one he immediately regrets.
"It was a split decision and I had to shoot him," he noted. "But as soon as Henry shoots Sam, there's a wash of emotions that go over him. But I think, ultimately, if I was gonna say one word, just, shock. He's shocked. As soon as he shoots him, he instantly regrets it and is in shock. He even asks, 'What did I do?' He's just in shock."
Ultimately, Henry makes the decision to take his own life, with Johnson sharing, "I like to believe that Henry is a God-fearing man and he saw that Sam had passed and he wanted to join his brother."
"Sam is Henry's will to live. He is his purpose," the actor added. "He would not be able to stomach living in this world, as harsh it is as it is, without Sam – especially after all of his efforts, after all that they've both been through: losing both their parents and just having one another. It was just a tough thing for Henry to have to stomach. He definitely would've been very depressed. It would've been on his mind. It would've eaten him away, would've eaten him alive."
Despite his character's untimely end, Johnson said that, as a fan of The Last of Us games, it was an "incredible experience" to be part of the show.
"The reception has been amazing," he raved. "I'm truly watching this as a fan."
As a fan of the franchise, he said he also appreciated the changes that have been made in adapting it for television -- such as making Sam slightly younger and deaf, which he is not in the games.
"Obviously, you just kind of grow a bit more of protectiveness over him because he's so young," Johnson said of his on-screen little brother. "But I think also with the added element of the sign language, I think it added a really nice layer of intimacy between them and also really allowed us to connect even deeper.
"The hardest part was learning the sign, but being able to deliver it in a organic and natural way, because Henry would have been signing with Sam for years," he continued. "So I really had to practice and practice so that it felt organic. Because, you know, Keivonn, he is a part of the deaf community and also me, playing Henry, I'm representing the same community. So I know that there's a responsibility on my part to make sure that I'm doing the best that I absolutely can to represent this community in a truthful and honest way."
The Last of Us normally airs Sundays at 9 p.m. PT/ET on HBO and HBO Max. Episode 5 debuts Friday, Feb. 10, at 9 p.m. PT/ET.