With the reveal of Mrs. DiLaurentis’ killer, Tuesday’s Pretty Little Liars put one of the series’ oldest mysteries to bed — or did it?

“Oh, nothing has been put to bed,” Andrea Parker — whose character, Mary Drake, was revealed to have killed Jessica, also played by Parker — tells TVLine. “You’d better get out of that bed and start running, bro!”

Parker admits that she was “very surprised” to learn of Mary’s involvement in her sister’s demise: “I had several conversations with Marlene [King] as Mary was being developed, and we were specific about her characteristics and her point of view. I didn’t really become aware of Mary’s true heart until we were well into these last episodes. As the actor, I was expecting her to remain darker. Without revealing too much, I think there is a genuine heart in there.”

Below, Parker further discusses her character’s latest twists — she made a baby with who now!? — as well as what the future may hold for Mary and Spencer:

TVLINE | This is definitely the first time I’ve interviewed someone who plays both the killer and the victim.

And I’ve definitely never played twins, with one who murdered the other, before! It really has just been such an incredible experience from start to finish. When they hired me in the second season, it was offered as ‘maybe a couple of episodes,’ and it’s really unfolded into one of the best gigs of my career. I’ve had such a blast, not only playing these characters, but the relationships I’ve formed with all of the actors who are really beautiful people. And the crew, who are the best in the business. And fans like I have never experienced — they’re so loyal and invested and magnificent. So, yay for me!

TVLINE | We’ve seen you play Jessica, and we’ve seen you play Mary — but last night, we saw you playing Mary playing Jessica. How do you get into that headspace?

Yeah, baby, I’m going in deep. I actually use a lot of music to get myself into different places emotionally; music is a big part of my preparation.

TVLINE | Do you have certain songs you like to listen to?

Oh yes, I made a very specific playlist for when I need to get into character as Mary. I’ve been considering tweeting it out. [Editor’s note: Do it!]

TVLINE | I don’t suppose that song Mary sang to Spencer is on there?

[Laughs] “Hush, Little Baby”? No, it’s definitely not. And I remember when I had to do that, I was like, “Why do you keep giving me songs? I have the worst voice in the world!”

TVLINE | I imagine the next time Mary and Spencer speak, it won’t be pleasant.

That’s true. It’s complicated! Families are complicated, and in Rosewood, it’s all magnified.

TVLINE | What can you say to the fans who are pulling for that mother-daughter relationship?

Mary and Spencer are going to spend a lot more time together, and all will be revealed.

TVLINE | Speaking of reveals, we also learned that Ted is Charlotte’s father.

Pastor Ted, you dirty dog, you!

TVLINE | Do you have any thoughts on that, since it directly involves Mary?

I think it’s fun. It’s another random explanation, and it’s all part of the history of debauchery that Mary comes from. For me, I’m just so happy that it sounds like — at least for a moment in time — Mary was actually living her life and enjoying it. So much of Mary’s past was painful, I was just so happy that she had a chance to find love.

TVLINE | I’d love to see those two in their college days. What do you think Mary could have possibly majored in?

That’s an awesome question, I should give that some thought. [UPDATE: Parker believes that Mary “has a doctorate in emotional manipulation, with a minor in medieval torture.”]

PLL fans, now that you’ve had some time to digest these latest twists, how are you feeling? Drop a comment with your thoughts — and any new theories you may have birthed — below.