[Warning: The following contains spoilers from Thursday's Grey's Anatomy. Read at your own risk!]

Teddy (Kim Raver) had a jaw-dropping blast from the past on Thursday's Grey's Anatomy, which not only revealed a part of Teddy's history that fans had no idea existed, but also put her cheating on Owen (Kevin McKidd) with Tom (Greg Germann) in a whole new light.

The heart surgeon was one of the handful of Grey Sloan doctors that went to a surgical conference in Los Angeles, where she ran into a former roommate Claire (Rya Khilstedt). They lived together in New York with a third roommate, Allison (Sherri Saum), who died in the World Trade Center on September 11th. The twist? Both Claire and Teddy were in love with Allison when she died. Allison and Claire were officially together though, and Teddy was having an affair with Allison behind Claire's back. The plan was to tell Claire about the affair and move out, but Allison died before they could, and losing Allison was the reason that Teddy enlisted in the Army. The former roommate and lover is also who Teddy named her and Owen's baby girl after.

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Facing Claire was a tough moment for Teddy, who was blindsided when Claire revealed that she knew about the affair. She had Allison's phone records pulled after she died and found out that Teddy was the last person that Allison tried to call before the towers came down. Claire forgave Teddy for what she did, but not before Teddy gave a moving speech about how it's possible to be in love with two people at the same time — probably talking about her self more than Allison.

The backstory wasn't the only major revelation of the episode. Teddy got her redemption with Claire and then headed to Richard's (James Pickens Jr.) presentation at the conference. After hallucinating that Catherine (Debbie Allen) had joined him the night before, Richard gave an off the wall presentation that had everyone watching alarmed. Maggie (Kelly McCreary) claimed he was having a stroke and the episode closed with Richard being rushed to the hospital, the Grey Sloan staff at the conference following close behind.

TV Guide spoke with Kim Raver about this development in Teddy's past, what it means for the future, and how the Grey Sloan staff will rally around Richard in the episodes ahead.

Kim Raver, Grey's AnatomyKim Raver, Grey's Anatomy

Let's talk about Richard first. What can you say about Teddy's reaction to his presentation and how the Grey Sloan staff is going to support him in the upcoming episodes?
Kim Raver:
I think everyone is shocked and extremely concerned because Richard is the rock. I don't think any of us have ever seen him sort of in this state. There's this beautiful coming together to kind of care for and see what steps we need to take to see what's happening. It's really a beautiful storyline in terms of everyone at the hospital coming together...[James] is so good in this role that it really is very moving. It's just really a wonderful storyline the way it plays out.

On the Teddy front, her relationship with Allison is a true revelation. What was your reaction when you first read this script?
Raver:
I had no idea. That's the amazing thing about episodic television — it's not like a movie where you read from front to back and everything is happening. [On TV], you can play this character for years and have your ideas about it. Krista [Vernoff, showrunner] opens up for us to kind of pitch ideas and I said, "There's such a great wealth for Teddy's history...We know a few really important things, but we don't really have a view into her backstory. Then Krista ran with it and came up with this. I was like, "Oh my God, that's amazing!" It was a huge a-ha moment, and it all made sense. I had no idea it was coming.

How does seeing Claire, remembering Allison, and having this moment of clarity affect how Teddy sees her situation with Tom and Owen?
Raver:
Look, Teddy is in like deep water. There's a whole thing of infidelity. I know that is causing a lot of feelings for the fans, right? I think what Krista is so great at doing, and Shonda [too,] is really talking about the complicated messiness of relationships and love. It's never just one thing or the other. It's like an amalgamation of so many [things]. I feel like this piece of the puzzle of understanding that that love is is amazing, and love is complicated, and love is messy — but also love Is love That's also what I love about it...I just know that, like, the beautiful thing of love is love and that this is the person that she was in love with. And so the loss of that...I don't think she ever processed it.

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It's not just like an affair for Teddy and her present day. She really loves these two different people. I think it's also going to lead to kind of exploring Teddy's own self love [and] not to get too like philosophical, but I think Teddy's fear of abandonment, because the people that she has loved she's lost. That this opens up a lot of doors for us to explore in terms of, "What is growth? And what is love to Teddy and what is self love and and how do you heal? How is she going to heal?"

She seems to have a moment of clarity when she's talking to Claire and gets her forgiveness, but is that going to stick when she returns to Seattle?
Raver:
I think it's like life. When you're kind of in crisis you have a moment of clarity, but that doesn't mean that it all of a sudden it just resolves itself. Which I think is great, because also, I think sometimes that can happen in television or film. I love that Krista has kept it complicated. We come back and it is still really complicated. So [Teddy] might have like a moment of clarity and lightness in this episode, but I think it's gonna take a lot of navigating to kind of get through the messiness that in her life right now. It's going to be still super complicated because I feel like her love is really deep. It's not just a sexual affair. It's really deep on both levels and so she's got to figure that out. She's navigating, so it definitely is really sticky when she comes back. It's not rainbows and unicorns yet.

As the protector of Teddy, are you rooting for either Tom or Owen?
Raver:
I am secretly rooting for one of them, but I don't think I can talk about that yet. I do feel that I know, in Teddy's heart, which person she should be with. Now whether that actually ends up happening — it's like real life. Who actually is really better for Teddy? I have like a gut instinct of what that is, but I think it's fun if we kind of play it out together.

Grey's Anatomy continues Thursdays at 8/7c on ABC.