[Warning: The below contains MAJOR spoilers for Transplant Season 4 Episode 9 “Who Is Mags?”]

Transplant says goodbye to Mags (Laurence Leboeuf) in the penultimate episode of Season 4.

Bash (Hamza Haq), Theo (Jim Watson), and June (Ayisha Issa) all attend Mags’ funeral in Montreal, with two of the three struggling the most. Mags’ mother wonders why Bash didn’t call them and argues Mags shouldn’t have been working when she was sick (rejecting her heart transplant). Also in attendance are Claire (Torri Higginson) and Bishop (John Hannah returns!), and after the service, Bash’s former boss finds him.

Bishop tells him not to blame himself, knowing how he feels about not saving his parents, and reminds him that he’s only alive because of him. Bash feels he didn’t deserve Mags, and Bishop comforts him before driving him back to York Memorial and encouraging him not to let this derail him.

“I was so excited to bring back Dr. Bishop, to have John back in our lives, however briefly,” creator Joseph Kay tells TV Insider. “Bishop and John Hannah have a great ‘everybody’s dad’ sort of persona. He can bring the hammer down in a way that’s a little bit scary, but he can tell you whether you’re on the right path or not in a way that’s really affecting. We knew that we had this great tool that we hadn’t used in a while, and I’ve been really fascinated in building to an ending that was circular and that ends us in a way where we started but with everybody doing a little bit better. And the show begins with Dr. Bishop giving Bash a chance and pulling him out of what we learned in Season 4 was a spiral where he thought maybe he would never be a doctor again, so to have Dr. Bishop be the one who can come back at this moment and at least offer Bash some paternal wisdom about how far he’s come, well, that’s just too exciting to not try to make work.”

Kay also points out that Bishop “was the kind of presence” that affected even those with whom he had a smaller relationship, like Theo and June. But bringing him back was also important for Claire and their relationship. “They have the only other real sustained romance in our show. She’s just spent the last season and a half going through essentially post-traumatic stress reaction to being assaulted in the workplace,” he says. “And to have him show up at this moment gave us an opportunity to give them a happy ending, which as far as couples go on Transplant, may not have been the happy ending that the larger portion of our audience wanted. But it was a relationship that I always really liked writing to and loved the way they played it. So it gave us this great opportunity to have to tie up Claire’s story and give her something.”

It was a way to give the character of Bishop something as well. “The last that we saw Bishop was that he was more or less facing a certain kind of obsolescence, which was upsetting for him, and to learn that he’s come back and still wrestling with that we thought was affecting. So he’s not just a tool to serve the rest of the characters. We thought there was a way to bring him back where the absence was still relevant for his character,” explains Kay.

The penultimate episode also features a flashback to the time of the series premiere, Bash’s aforementioned save of Bishop that brought him into York. This scene of Bash and Mags was newly filmed, not just deleted, Kay confirms.

“Everybody had aged, no CGI budget for us in de-aging on Transplant,” he says with a laugh. “We filmed it, redid everybody’s hair. It was a late idea. That wasn’t an original idea. It was one that came to us in the writing and in the writing organically of the fourth season where we tell a story about Bash having essentially failed at becoming a doctor again, giving up, and then winding in this moment where he’s about to get the chance and for it to be Mags who had been the one in our pilot to figure out that Bash was a hero before anybody else and then to essentially tell Dr. Bishop, ‘Hey, this guy is a hero.’ When it occurred to us, we thought it was too good to pass up. And everybody was excited to fake being six years younger.”

June’s also struggling after her close friend’s death. She even jumps at a chance to return to work after the funeral, and it seems like that’s where she’s most comfortable.

“June’s not perfect. She tried and she’s changed, but she’s still June. So I don’t think that’s a surprise to anybody that a situation like that might’ve pushed her a little bit too far too soon,” points out Issa.

As for what it would take for her to not be most comfortable at work?

“Despite her facade, which is liking to remain kind of somewhat detached, I think the reason she does that is to protect herself because she feels so deeply for people because she cares so deeply about people’s feelings. And for a lot of people it’s like that. For me, it’s like that where, for a long time, it was difficult to manage, ‘Okay, well how do I care as deeply as I do about other people’s experiences and feelings and needs as I do without completely abandoning myself?’ So finding that healthy place is a process for a lot of us, and I think that she’s in that process and I think that she learned a lot of that from Mags and from her experiences and from dealing with Novak [Gord Rand],” Issa says.

That’s where she sees June’s journey to motherhood coming into play. “She recognizes that as being a challenge, that she’s willing to undertake that. I think a huge part of what terrifies her is that exact same thing of how is she going to balance all these things. I think that if she’s successful in that, that is something that’s going to help her do that,” according to Issa.

It feels like June needs Mags, her friend, to process Mags’ death, and Issa agrees, but adds, “I think that the fact that she wasn’t there was also maybe exactly what she needed in the sense of she relied on Mags so heavily for a lot of that stuff, that this is a next step in that which is going out on her own and having to apply all that stuff that she learned from her interactions with Mags and going forward and maybe asking herself that question of, what would Mags do in this situation? I think that that might be helpful.”

What did you think of Mags’ funeral and Bishop’s return? Let us know in the comments section below.

Transplant, Series Finale, Thursday, July 17, NBC