Carl skedaddles, leaving Walter alone to wonder if he should start pegging the legs of his Guess jeans, and then Elizabeth strolls in. "Love, you didn't come home last night. I was worried about you," she says ... and then she spots Peter. "How?" she whispers. Walter explains that the other Peter he showed her - this boy - was dying to. "It was the only way I could save him," he says. "Well, at least it's not like in that recent bestselling novel Pet Sematary by Stephen King," says Elizabeth, as she walks over to get a closer look. She starts crying as she gathers the sleeping Peter up in her arms. "Oh, my baby," she says. "Elizabeth, don't. He's not ours. I have to take him back," says Walter. Elizabeth just looks at him, her eyes a mixture of fear, anger, sadness and warning. Yeah, you're not taking this kid back, Walter.

Back in the present day, that's exactly what Walter tells Olivia, that he realized at that moment that he could never do what he fully intended to do. "The way she looked at him, I saw in her what I feared most in myself when I saw him: that I couldn't lose him again," he says.

That was the first hole, Olivia, says Walter. "The first breach. The first crack in a pattern of cracks, spaces between the worlds. And it's my fault."

He shakes his head, fighting back tears. "You can't imagine what it's like to lose a child," he says. Oh, here I go again. You know what that last sentence means to me? Walter knows he would, given the chance, do it again.

Daniel is a writer in Newfoundland with a wife and a daughter, whom he would unhesitatingly destroy the universe for, if it came down to it. It probably won't come down to it. Follow him on Twitter or email him at danieljdaniel[at]gmail.com.

Watch the episode here, discuss it in our forums, then see the show's Most Memorable Moments!