'Person of Interest' Finale: Behind the Scenes With Amy Acker and Sarah Shahi

It’s not often you get to see a woman casually strolling down a hall putting down bad guys, much less two of them. But that’s one of the many ways that “Person of Interest” sets itself apart from the pack. Sarah Shahi and Amy Acker play former assassins now working to save people rather than kill them. Yahoo TV has exclusive behind-the-scenes footage from the season finale, “Deus Ex Machina,” and we asked the two co-stars about each other and kicking just as much butt as the men.

Shahi says her favorite moments from the show are “any time I get to do a stunt. I love beating up on boys!” Acker also loves playing the action moments, recalling “the scene where I walked through the hallway and shot all the Decima guys without looking.”

Of course, that’s not all Acker enjoys doing. Since being added to the main cast this season, Acker’s character, Root, has had plenty of screen time to grow. She began Season 3 locked in a mental asylum: “I loved the first episode and getting to say that speech to the psychiatrist,” she shared. “I loved every scene I ever got to have with Michael Emerson.” Those scenes with Harold Finch contain some of the most affecting moments for her character.

[Related: How a Veteran’s Experience in Iraq Led to a ‘Person of Interest’ Episode]

She even enjoys the hard shoots — shooting in New York can be especially difficult in the winter. “I loved — even though it was freezing — the great stories I have from Episode 17, like laying on the frozen street in negative-10 degrees.”

The hatred, rivalry, and friendship between Root and Shahi’s Shaw make their relationship unique, and both women enjoy portraying it. “I love working with Amy,” said Shahi. “She and I are very similar. And when you are part of a boys’ club, it’s nice to have some females.”

"I have loved Sarah since I first tortured her with the iron," said Acker, describing a relationship that sounds more like sisters than work buddies. "She is so much fun to hang out with on set and off. I am always excited when I get to have scenes with her, because I love the relationship between the two characters, so those scenes are always really fun to play.

"I feel like you see a lot of male relationships like that onscreen — where the two guys bicker and don’t get along and are always hiding that they care about each other," said Acker. "But as far as two women, you don’t see it too often." Acker likened the duo to Sandra Bullock and Melissa McCarthy from last year’s buddy cop flick "The Heat." "I kept thinking what Shaw and Root would be like as partners. Made me want to do a Root/Shaw team-up episode more."

[Related: 'Person of Interest's' Amy Acker: Root Is 'Questioning Everything She's Believed In']

As the above video shows, they do team up in the finale, and they will almost certainly do so in Season 4. And they’re both hoping the action gets even crazier. Shahi wants to get “dangled from a building like Tom Cruise” in “Mission Impossible.” And Acker looks forward to getting her hands dirty. “I would love to do some fighting scenes. Root mostly uses her Taser or just shoots people, so I am not sure that is in her skill set.”

She suggests having Root take Krav Maga classes over the show’s summer break. “Or better yet, a scene where Shaw is training Root,” she says. Though, Shahi’s not quite as sure that their characters are that close yet. “They may kill each other, but they could try!”

Tuesday’s season finale will be the last chance to see the duo at work until Season 4. What are you hoping to see? What new skills do you hope they’ll pick up during the show’s hiatus?

"Person of Interest" airs Tuesdays at 10 p.m. on CBS.