Did you know in advance that Martha was going to have such a busy, feverish Season 4?

When Clark took off that wig at the end of last season, I was like, “Oh, here we go.” I knew that all the stakes had to be through the roof immediately, and I made sure they were. I really wanted to pull at those heartstrings.

The departing scene is shockingly emotional. How was it shooting something so intensely heartbreaking?

Matthew directed that episode, and it was quite a lot for me to wrap my head around, with Martha coming to that point of accepting everything and willingly getting on the plane. There was a lot of back and forth with the J’s [the showrunners Joe Weisberg and Joel Fields] about it, but that was the story they wanted to tell — that Martha managed to do it and that maybe she was going to be all right. She wasn’t decimated. She wasn’t screaming and crying and kicking. She was in some other numb, calm, dazed, shocked place. It was at 3 o’clock in the morning in a field in the middle of Long Island somewhere when we shot it. And it was sad, yeah.

So Poor Martha is a lot stronger than she sometimes seems?

I think people perhaps underestimated her as a character and as a woman. She’s a sweet idealistic soul, but she’s not a doormat. She can be a loving, devoted wife but still have demands and stand up for herself. She can go to church every Sunday and steal classified documents once a week, too. I’m very proud of the fact that the women on “The Americans” are written to be equally complex as the men.

You’re quite glamorous in person but Martha is not. Is there a trick to playing such a subdued character?