"As the season progressed it became increasingly clear that it was going to be our last season," says executive producer Matt Olmstead about the upcoming end of FOX's "Prison Break," which returns for its last wave of episodes on Friday. "It turned out to be kind of a benefit to us in that we were able to really set up things that were going to pay off at the end of the season and what would be the end of the series." Olmstead talked to our Jim Halterman last week and shared his thoughts on how the fates of our favorite escapees will end and to expect more than a few surprises along the way.

While cancellation for some series comes too late to give the writers a chance to properly wrap up storylines, Olmstead explained that, thankfully, that wasn't the case this time around. "It was a bit of a luxury in the sense that we had the time to platform the ending as opposed to going on hiatus like some shows have to do and wait to hear if you're going to come back or not and you don't and you don't have a chance to wrap up a serial-like show, which deserves to be wrapped up properly."

While the ultimate endings are under wraps, Olmstead did offer up a few teases as to which characters might show their faces again in these last episodes including the Mom character, who showed up in the last original episode that aired in December. "She plays a big part of the last few episodes, a lot of secrets are revealed and Michael and Lincoln are certainly shook in terms of who they are, where they came from and at a certain point they're wondering is this the truth or are they trying to be divided and conquered, so to speak."

And, as fans of the series will tell you, "Prison Break" wouldn't be "Prison Break" without a few unexpected twists and turns? "We have a big surprise reveal, which I won't tell you who it is, but a returning character who comes in late in the game when the wheels are coming off everybody," Olmstead teased. "He's either there to save the day or to hijack the whole thing for his or her own benefit. So the big reveal of a returning character that having viewed it, obviously, pays off very nicely."

While episode 22 will serve as the official series finale, Olmstead also talked about the "Final Break" episodes, which will reportedly be released as a standalone DVD on July 21. "What happened was when we were breaking the episodes we had a storyline that we didn't know where, it didn't really fit. It kept getting moved along down the episodes as the season went along. Then we had a conversation with the studio in terms of, this is really a cool story that we want to tell and it plays standalone, which would be a two-hour. So they, the studio, and we creatively went ahead and did it for episodes 23 and 24, not knowing for sure where it would air, network or whatever, but knowing that it would certainly in some or fashion because the story for us was really compelling and also having viewed that in its entirety, that paid off and was a good idea."

However, he did explain how these extra episodes play out in the timeline of the final season of the series. "Everything gets wrapped up and then in the last act there's a jump forward like four years from now. We show the characters where they are and some have won, lost; it's bittersweet and this two-hour (episodes 23-24) that we had in mind kind of plays in that middle period, that wrinkle in time."

The fate of the regular characters may be coming to an end but Olmstead discussed how those fates had changed or were adjusted through the course of the series. "There were certain things that in terms of Michael's fate, Lincoln's fate, Sara's fate, all the characters' fates, that we had tossed around as the show went along. Down the road I always wondered what's going to happen, where will we be? So it was kind of a little bit of a game that we had in terms of what are the last images you want for the show? Obviously that kind of got more traction this season when we knew this was going to be it."

The romance between Michael (Wentworth Miller) and Sara (Sarah Wayne Callies) will also unfold in an unpredictable way in these last episodes. "For a while there they were, just for like an episode or so, it felt like they were kind of Bonnie and Clyde. It worked for one episode, which is kind of coming up," Olmstead explained. "It was that same fear of what do you do with two characters that there's a real charged, fresh aspect to their relationship if they're stuck together do they become the Lockhorns? What are they going to do after a while? That's kind of the reason why in season three we had her character 'killed' because there's almost a disservice to the actor and the character like what are we going to do with her once they're together because there's always been walls between them?"

Speaking of Sara's "death," the reasons behind that choice were important for where her character is in this final season. "We found a way in this season for this kind of torture that she suffered at the hands of Gretchen and company in season three off-screen that helped kind of put this new wall between her and Michael and it's a wall that inhibits their intimacy. Finally at the end of the season I can say that wall comes down, but there are unexpected ramifications to that. So, what seems like two people are joined at the hip want the same thing there's a bunch of curve balls that are thrown at them in the finale. Ultimately it's bittersweet, but very satisfying."

Asked if he and his fellow producers had thought about future stories in the event that the show had not been cancelled. For the sake of the series, Olmstead suggested that it might actually be a good thing that the end is approaching. "The ideas that were tossed around in terms of what could be a season five were pretty thin. And my fear is that even if it went that way it would have limped out; it wouldn't have gone out strong and just having been to the wrap party that everybody went to, there was a real feeling of accomplishment and there was no sense of we got caught short or it was we could have had more years or we wished we had more years. It felt like the story played out and there was, having looked at the series finale, the four seasons play as a piece, as opposed to this season strung along and ultimately kind of fading out."

Finally, Olmstead admitted there was one thing he feels regret about � not having more opportunity to shoot at night even though it did help keep an important facet of television production in line. "As I look back on this there are no real missed opportunities for me and the only thing is kind of budgetary-wise we were always proud of the fact that we stayed on budget for a couple different reasons. So we were unable to film at night as much as we did in season one and for a visual aspect for me that was basically the one thing I wish we could do more. But in terms of storytelling or getting an actor or any of that kind of stuff, I sincerely have no regrets."

The final five episodes of "Prison Break" begin this Friday with a repeat of the last original episode at 8:00/7:00c and then a new episode at 9:00/8:00c. The next three episodes will air at 8:00/7:00c on Fridays with the two-hour finale airing on May 15.