[Warning: This story contains spoilers from Thursday's midseason finale "Get Up, Stand Up" episode of Grey's Anatomy.]

ABC's Grey's Anatomy went into its winter hiatus with a massive cliffhanger Thursday. During the season 10 midseason finale, April's (Sarah Drew) wedding day didn't go according to plan (shocker!) as her bridesmaids navigated personal and professional woes.

After April taps Meredith (Ellen Pompeo), Cristina (Sandra Oh) and Arizona (Jessica Capshaw) to replace her sisters as her bridesmaids, the trio of Grey Sloan Memorial docs did nearly everything in their power to steal April's thunder. Meredith and Cristina had it out in one of the long-running medical drama's most hurtful confrontations, as their personal-versus-professional feud escalated to new heights that could potentially set the stage for Cristina's exit from the series. Derek (Patrick Dempsey), meanwhile, gets a call from the president (paging Scandal's Tony Goldwyn for a crossover!) that could change his -- and Meredith's -- life and career.

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Arizona, meanwhile, finally feels comfortable in her body again, as Callie (Sara Ramirez) continues to make strides in her research that could ultimately improve Arizona's prosthetic, helping to explain the emotional rift between the duo.

Shane (Gaius Charles) sees visions of Brooks (Tina Majorino) and makes a startling confession to Webber (James Pickens) about his role in her death, after going on a full-on Cristina-like power play that comes after he fudged his hourly allotment in his bid to become the best by any means necessary. It could, however, come at the expense of Alex's (Justin Chambers) estranged father, who may not make it out of surgery.

But it was the closing few minutes of the episode that provided one of the hour's biggest cliffhangers when, after apologizing to Stephanie (Jerrika Hinton), Jackson (Jesse Williams) interrupts April's wedding to Matthew (Justin Bruening) to profess his love. "April, I love you, I always have. I love everything about you. Even the things I don't like, I love. And I want you with me. I love you, and I think that you love me, too. Do you?" It comes after Jackson and Stephanie shared a sweet moment in the OR, when he shares a valuable lesson the late Mark Sloan (Eric Dane) taught him: "If you love somebody, you tell them, even if you're scared it will cause problems or burn your life to the ground. Say it loud and go from there."

The Hollywood Reporter caught up with Williams to get the scoop on what's next for the former (and potentially reunited) couple.

Where will the second half of the season pick up? Will there be a time jump or will we see the immediate aftermath of Jackson's objection?

It's going to be a combination of the two: you'll see what happens and the impact it has on everyone. This is going to have a devastating affect on Stephanie. In situations where you have somebody being left at the altar, it's usually the dashing bad guy versus the really honorable guy. Is she going to go with the jerk or is she going to go with the good guy? In this situation, Matthew and Stephanie are Jackson's victims. They don't deserve this and are both wonderful people who haven't done anything wrong. Sometimes love gets in the way of what you're supposed to do and who the person on paper is supposed to be, and that love by design and paint by numbers situation doesn't really work. Sometimes there's collateral damage, and Matthew and Stephanie are good examples of that.

You'll see it came as a huge surprise for Jackson, and that it wasn't premeditated. It was just a compulsion to blurt it out. Sometimes when you act impulsively, you have a "WTF did I just do" moment, and we're going to see that. I cant say what April's response is going to be, but I can say that Jackson is going to have a, "Oh my God, what have I gotten myself into?" moment at some stage in the very near future. Anytime you think there's solid ground, it turns out to be slippery.

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After so many opportunities to get back together, why would Jackson object in the middle of the ceremony? What changed for him?

That's been my question as we've been developing story. He has been in stages where he's said to himself, "I'm over this, I'm moving on," and you keep your legs moving so that you don't have to stop and deal with it. It's not conscious denial because he is trying to treat a sickness: "I'm having my soup, getting fresh air and moving on with my life." At the wedding, sitting there is the first real moment of stillness for Jackson, where he realizes that this is not something that he will have to deal with in the future; it's something he can't talk himself out of. He's had these opportunities -- she presented it to him at the top of the season and at the end of last season -- and he said no. It didn't make sense on paper: it's not healthy; they shouldn't be together. But when they're in the same room, chemistry is chemistry, desire is desire and nobody understands the other person better than Jackson and April do. It becomes this undeniable truth that Jackson was and April were both trying to heal themselves from it. They were both trying to paint by numbers and do it "right" -- and they've never done it "right." They rushed into this and did it wrong and were told that they shouldn't be sleeping with their friend, shouldn't be having expectations of the relationship. They were trying to follow the proper steps, and life is sloppier than that.

Where do they go from here? Could we see them try again since it seems Jackson has broken things off with Stephanie?

Stephanie is going to be hurting; you can't bounce back from that. It's public humiliation, an ambush and a stab in the back. I doubt that any of us would want to hear, "I didn't meant to. I had no idea." In many ways, it's a selfish act, but without selfish acts, you don't necessarily get what you want unless you ask for it. What's interesting is that Jackson and April, as much as they seem to have been this couple for what felt like seasons, they've got this established connection. Technically, they've really never been together as a couple. They never dated, they never had the awkward first date, they never had doubts about meeting their families, they never got to have the get-to-know-you-romantically part of the equation. They thrust themselves together and skipped a few steps. What is Jackson proposing when he stands up there? It's what they have to figure out: Do you want to go to lunch with me? Do we want to date again? Do you want to start the courtship process from scratch? Do we want to pick up where we left off? Do we want to get married ourselves? Is that way too much too soon? Do you want me to pay for the wedding? Should we use [the wedding] right now? There's a million ways for it to go, but what it does shine a light on is what constitutes the metrics of love and an established relationship. Jackson and April have never been a couple. Jackson's mom (Catherine, Debbie Allen) doesn't know about it; April's family doesn't know about it. They were just two people sleeping together and people probably viewed it as a lusty, trivial thing, when I would suggest there's as much chemistry between those two characters as any on the show.

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What can you say of how April will respond to Jackson's declaration? Will she be angry?

There are certainly victims in that scenario. Jackson certainly hurt Stephanie, but no matter what April says, the fact she's standing there pausing and considering it and not shutting it down immediately -- how is Matthew supposed to feel about that? Can she turn back and say, "We're going to move on and keep this marriage ceremony going"? That might not be realistic for Matthew. It's a complex and muddled ball of feelings here, and Jackson really threw a wrench in the whole thing.

How much of Jackson's sudden change of heart is based on Mark's "Say it loud and go from there" words of wisdom?

It was an accidental mirror that he put up in front of himself and an accidental reflection. It was a really interesting thing that Mark said, and it stuck with him and in the hours that follow. Jackson has been sitting in the pew and realizes, "That's me that I'm talking about. This is one of those opportunities where you're supposed to blurt something out and do something about it. Everybody else be damned, and you just have to take care of yourself." Nothing about what Jackson did is premeditated -- he wasn't even going to go to the wedding. But when it happens, a lot of has to do with Mark being a big figure and mentor for him. He saw what happened when Mark waited until the last minute. Life is short and Jackson's friend and mentor died before being able to patch things up with and go for broke with the woman that he loved (Chyler Leigh's Lexie), even though that was painful for Jackson since it was his ex-girlfriend. He's also been in Matthew and Stephanie's shoes and pursued something with someone who has no business starting something new because they were in love with someone else. While Jackson was dating Lexie, he always saw her looking at Mark and Mark looking at her. When things aren't over, it's hard to put new bricks on a slippery foundation. He's been on the side of that, which you'd think would make him more sensitive to that, but he also knows you have to take advantage of the now, and you don't want to be like Mark. You don't want to be in a situation where you have a lot of regrets on the table. So f--- it, let's just do it, and people will get over it. He's also realizing the truth for the first time: that he never told April that he didn't care for her or that he didn't want to be with her. He said, "I don't think you want it for the right reason, and you're scared, and you're marrying this guy because he's terrific and not because he's the guy for you at this moment." There were a lot of caveats and comments but not a direct address to how they felt about each other. Jackson and April have never said, "I love you," to each other until that moment when he stands up in the church. There's something profound, spontaneous, romantic and authentic about that because it's the first time either one of them say they love them to each other. It just happens to be at the wrong person's wedding. Maybe it's because they spent too much time trying to make their relationship perfect instead of just blurting it out and figuring out the rest later. It's where Mark's words were really helpful.

Jackson stood up twice. What was that about?

That represented how spontaneous and how reactionary this was for Jackson. It's Jackson realizing he has to do something, and seeing the room go silent and the faces looking back at him when he understands the weight of what he could potentially be doing. Then taking a breath and reaffirming that this isn't a choice; it's something he has to do that's actually happening. What he realizes when he sits down that first time is that he doesn't have time to sit there and try to rationalize it -- he's been doing that to his own detriment for the past six months or two years or however long. [He has to] stand up and say the truth and figure out the rest later. It's a physical illustration of self-censorship and catching himself and trying to be tactful and have some grace and wait for the right time, but there's no more waiting and he has to do what he has to do.

What did you think of Jackson's declaration? Hit the comments below with your thoughts. Are you Team Jackson? Grey's Anatomy returns for the second half of season 10 on Thursday, Feb. 27 on ABC.

E-mail: Lesley.Goldberg@THR.com

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