Blindspot star Sullivan Stapleton on Weller's big, brutal episode

Warning: This article contains spoiler's about tonight's episode of Blindspot.

Weller had a hell of a time this week on Blindspot.

After getting captured by Ivy Sands (Julee Cerda), Agent Weller (Sullivan Stapleton) found himself in real danger. Strapped to a chair and drugged, Weller began to hallucinate, seeing a number of things including figures from Blindspot's past. Bill Weller (Jay O. Sanders), an imagined grown-up version of Bethany, and even Oscar (François Arnaud) show up to mess with Weller's head. The team works fast to find and save him before Weller gives them up to Madeline Burke's (Mary Elizabeth Mastrantonio) people. All of that doesn't even take into consideration that last he knew, Jane (Jaimie Alexander) had been shot, and his daughter Bethany was in the hospital for an unknown reason.

In the end, Jane survived her gunshot wound, Zapata (Audrey Esparza), who the group learned is pregnant with Reade's (Rob Brown) baby, brings Weller home, and the team was back together.

Star Sullivan Stapleton tells EW about exploring Weller's mind, where he stands with what his father did to Taylor Shaw, Jeller, and more.

ENTERTAINMENT WEEKLY: How did you feel about getting to dive into Weller's mind like this?

SULLIVAN STAPLETON: Working on shows like Strike Back and Blindspot, you start with the characters and then begin to develop. Our writing team has given me great opportunities to explore a real rollercoaster of emotions with Weller and the team.... Weller goes through a lot with the hallucinations. Seeing how far we were going to break down the character was fun. On shows like this, the days with stunts and fights are the good ones – explosions, great. Then you go to work every day and have to bring yourself to a dark place and crying your eyes out for a lot of it. It's hard, but that was a blessing to me as an actor. Being strapped to a chair, getting angry and upset, it was a tough week, but it was great. It was nice to explore those areas of Weller, and considering this is the final season, it's nice to show what the impact all the fighting and things they've been through is important.

Weller has had issues with the team's new situation. Most recently, he clashed with Jane over information about his daughter's health. What is it about Weller that conflicts with how the team is operating to clear their names and survive?

It really affects Weller because that's his daughter, and that information was kept from him. It started to show cracks in the team, this new situation is having its effect on them, and it's a hard thing to go through. Like everyone, Weller is trying to clear their names, take down this evil group, and hearing that news has deeply affected it. It's a scary place to be as a parent.

Weller and his father's relationship has always been complicated, but what was it like to act opposite Jay O. Sanders again as Bill Weller?

I loved it. That was a character I was grateful they brought him back. Bill is his father, so he has a massive impact on Weller, and it's complicated, but working with Jay again was just great. He's such a great man and such a great actor. It was a nice moment, especially knowing it's the final season. It was nice to reunite with him again and get to say goodbye.

Blindspot has shifted focus away from Taylor Shaw since we found out she's not Jane, but for Weller, she's a massive part of his childhood and life. Where do you think Weller is on that journey?

It's a hard thing for Weller. Going through life, those things that happen to us in childhood have a huge effect on our lives, and they live at the back on your mind. Weller having a daughter has made him go over what happened [to Taylor]. He obviously did blame himself for what Bill did, and we've seen that over the course of the series. I'm hoping he can close that chapter and focus on his daughter now.

The whole ordeal was incredibly difficult for Weller, but in the end, he seems to have a more positive outlook. How does this experience change Weller?

Having been tortured and broken down and driven deep into his mind, I think he learns that you've gotta work through things and work on being a more positive force on the team. Weller and the team have gone through some really dark times and met really evil people, which does start to have an impact on the characters. Weller has grown up and has started focusing on his family and the positive things in his life, but he's always going to fight the good fight. Now he's going up against Madeline.

Within that, you have this great pain of losing Reade, and then he finds out that Tasha's pregnant, so there's something positive to focus on. And there's Bethany too. He can just focus on making sure that they grow up in a better world.

These last two episodes have been tough for Jane and Weller. Throughout the series, what are some of your favorite of the couple's moments?

Wow. I think one of my favorites is the fight that they have against each other when Jane turns into Remi. She challenges Weller, and they have to fight each other. That to me, as an actor after having worked with Jaimie for years, that was great because they are this strong married couple, and they end up in this huge fight. That was a fun change for the characters and us as actors.

There's also a scene where they are going for a run together with Bethany in a pram. They are laughing with each other and having fun. It was nice to see them enjoy time together.

What does it mean to you that Blindspot is getting a planned ending?

For me, it's that funny thing. I was in this place at the end of season 4, and I didn't know if we'd get renewed. It would be a shame for the series to end that way and not get the chance to put an end to the story and wrap things up. When we found out we were renewed, I was happy we'd be able to ride it out. Getting half a season gave the writers the opportunity to end it as they wanted. And I love that I thought that was a great way to go out.

We finally get to see what happens and see where the writers take us. They took us to all sorts of places in the final season. To find out we could end it that way, and we were supported that much, it made me really happy.

Blindspot airs Thursdays at 9 p.m. ET on NBC.

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