The Last of Us Season 1 has concluded, wrapping up with a gripping and violent season finale that fans are no doubt excited to see continue with the forthcoming second season. Two of the stars of the finale have discussed the Season 1 finale, including the pivotal sequence that kicked things off. Spoilers for The Last of Us follow below.

The Season 1 finale opens with a flashback showing Anna (Ashley Johnson) trying to outrun an infected while pregnant with Ellie. She evades the infected long enough to barricade herself into a room, but her foe eventually breaks in. It bites Anna, and in the struggle, she kills the infected and gives birth to Ellie. Unfortunately for Anna, she becomes infected, too, but Ellie lives and is immune.

Some TV shows and movies use CGI or dolls in the place of very young babies, but HBO’s production featured real babies. These were twin 12-day-old babies. Johnson recalled that one of them, a girl named Mila, was a better actor than her twin brother.

“Mila was killing it, and the boy was just like, ‘I don’t know if I’m into this,'” Johnson told Variety. “But it was an intense environment. There’s screaming, the baby is covered in jam and KY jelly and it was a little chilly. It worked for the moment of wanting to care for them; I wanted to hold them and keep them warm.”

Merle Dandridge, who plays Marlene and was heavily involved in the scene featuring Anna and baby Ellie, said the fact that real human babies were used on set helped hammer home the intensity of the scene.

“It added this incredible element of surprise, beauty, and astonishment. Those babies were beautiful in their performances and heartbreak, and it brought a whole other layer between Ashley and me in that scene,” Dandridge said, adding that one of the babies peed on her a few times.

With Anna infected from the bite, she urged Marlene to shoot her and take Ellie to Boston. Marlene initially says no, saying she can’t bring herself to kill her friend, but she eventually turns back and ends Anna’s life.

The giraffe in the season finale was real, too, not CGI.

Also in the interview, Johnson spoke about wearing a pregnancy belly suit for her scene as Anna. She tripped a few times during scenes that made it into the final cut, and that was real, because her belly was so big that she could not see her feet. “It’s just this huge belly, you can’t really see anything. It was cold out there, but I was sweating. It was a little muddy, so it was hard to run, and there were branches. That adds to the stress; it was a good workout,” Johnson said.

At one point, there were plans for an entire game about Anna, which would have culminated in Ellie’s birth, but that game never materialized. While the season finale showed Anna for the first time and revealed the circumstances surrounding Ellie’s birth, we still don’t know who Ellie’s father is or exactly why she is immune.

The story will continue in Season 2, which will adapt 2020’s The Last of Us Part II, and a third season could follow.

As for the game series, Naughty Dog is making a new The Last of Us multiplayer game. After that, Naughty Dog might make The Last of Us Part III, or it might not.