That plot twist reaches a point of no return in the seventh season finale of ABC’s first responder drama. After catching his father kissing a woman who looks like his deceased mother, Christopher locks himself in his room overnight and refuses to open the door. Eddie, who begins to spiral out of control with guilt, calls his best friend, Buck (Oliver Stark), to help diffuse the situation with Christopher. But Eddie doesn’t know that Christopher has called in reinforcements of his own: After barricading himself in his room, Christopher calls his grandparents, Helena (Paula Marshall) and Ramon (George DelHoyo), to fly him to Los Angeles and bring him back to Texas for at least the summer.

The news isn’t well received by Eddie, who has raised Christopher pretty much on his own, with Buck’s help, for the past six years. But it’s not until Eddie sits down with his parents—specifically his estranged father, with whom he’s just reconciled—that he realizes that the best thing he can do is let Christopher go, even if their separation is only temporary.

“I know you’re mad, but you need to hear me: I love you, no matter what,” Eddie emotionally tells Chris, forcing him to look him in the eye. “You want to go with your grandparents? Fine. I hate it, but I love you. So I’ll let you go, but you can always come back. If you change your mind in five minutes or five months, just say so, and I’ll come get you, okay?”

Speaking about that heartbreaking goodbye scene, Guzman told The Hollywood Reporter in the conversation below, “I think there’s a full recognition that Eddie is no longer the best part of Christopher’s life, that he’s no longer the best and healthiest version of Christopher. Not only is that devastating for Eddie, but now coming to terms with that fact is something I don’t think Eddie has really come to terms with [yet]. We’re going to explore that in season eight.”

Eddie will have to deal with not only a new dynamic at home, but a new work life as well. Suddenly, after his team was honored in episode nine for their bravery during the disaster on the massive cruise ship earlier in the season, Captain Bobby Nash (Peter Krause) secretly submitted his resignation from the 118, believing he didn’t deserve to be recognized as a leader. Bobby’s decision stems from the guilt he still carries for starting a fire in Minnesota years ago that killed 148 people, including his wife and two children. After saving himself and his current wife, Sergeant Athena Grant-Nash (Angela Bassett), from a fire that engulfed their home and then surviving a potentially fatal heart attack, Bobby realizes, once again, that being a firefighter is his true calling, and he decides to return to 118. But there’s just one problem: the LAFD has decided to replace Bobby with none other than Vincent Gerrard (Brian Thompson), the stubborn former captain of 118, creating a clear divide and a source of tension within the tight-knit fire department. Below, Guzman discusses what the season finale could mean for the future of the show, why he thinks Eddie and Christopher’s relationship has changed irrevocably, and how he’s tapping into his personal life to find strength in Eddie’s vulnerability.

*** When we spoke a few months ago, he mentioned that he was relishing the opportunity to show a softer side of Eddie after years of turmoil, but he hadn’t yet read what happened in the second half of the season. How has Eddie’s latest storyline changed your understanding of him as a character? What new layers have you discovered in your portrayal of him this season?

Those are great questions. I think we already know who Eddie is, who he’s been, and who he’s trying to become. So we’ve had that sense of direction. But now, through all the obstacles that have come along,