Randall Puts Rebecca Between a Rock and a Hard Place on ‘This Is Us’ & Kevin Definitely Won’t Like It

*Warning: Spoilers ahead*

If you’ve been missing Jack (Milo Ventimiglia), then it’s your lucky day because This Is Us season four, episode 17 imagines what would have happened if he’d survived the fire. Spoiler alert: Things are totally different. When Randall (Niles Fitch) finds out that Rebecca (Mandy Moore) knew where his birth father was all along, he begins to resent her. We see Randall meet his birth father, William (Ron Cephas Jones), with Jack. Over the years, they grow closer and Randall is lucky enough to have two dads. He still resents Rebecca, until Beth sets him straight at the dinner from episode five.

Jack, Rebecca and William meet their first grandchild, Tess, and adult Randall (Sterling K. Brown) helps William recognize he has stomach issues so they catch his stomach cancer early. When Rebecca starts having memory loss, Jack is right there with Randall to find solutions…but then we realize this is just a fantasy (duh) and Randall is exploring what it’d be like if Jack had lived with the help of his therapist, Dr. Leigh (Pamela Adlon). She asks him to be realistic and Randall begins to understand that not everything would have been perfect if Jack had lived. Through these exercises, Dr. Leigh helps Randall realize that he’s secretly still holding on to resentment toward Rebecca because she hid the fact that she knew who his birth father was. This hits Randall hard.

So, he calls Rebecca and tells her how he’s feeling—not about his resentment but about the clinical trial. He’s aware of his resentment but he doesn’t want to ruin what time he has left with his mom rehashing the past. Instead, he tells her he needs her to do the clinical trial because he can’t live with any other outcome. She agrees, albeit reluctantly.

And now we think we fully understand why Randall and Kevin (Justin Hartley) really end up fighting. We’re just speculating here, but it seems that Randall and Kevin won’t just disagree because of sibling rivalry, or because Randall always thinks he knows best, but because of a wound he’s holding onto that makes him unwilling to imagine a world in which he loses his mom. Since Kevin isn’t in tune with that part of Randall’s psyche, he won’t be able to understand where Randall is coming from and will see it as Randall being Randall. But really, he’s desperately trying to fill a decades-old void and an unforgivable breach of trust.

Next week, the This Is Us season four finale airs, and from the looks of the promo, we’ll finally get to see the fight play out.

It also appears that grown-up baby Jack’s wife will welcome their child (um, was that the same doctor that delivered the Big Three?!) and Kate and Toby see someone totally unexpected. Who could it be?

We can’t wait to see what happens with the This Is Us season finale airs next Tuesday, March 24, at 9 p.m. PT/ET on NBC.