Grey's Anatomy's executive producer Shonda Rhimes has confirmed to me exclusively that a beloved character will die in the ABC drama's May 17 season finale. "A lot of our writers were crying, which is a very rare thing," she says. "There's some really shocking, horrible moments."

It can't be worse than the bloodshed two years ago when a crazed gunman hunted the doctors like animals, can it? "Yeah, it is," says Rhimes. "People's mettle is going to be tested."

Writing the episode, she adds, was sheer "torture... I've been sitting with my head in my hands for days. I understand the choice I made, but it scares me how fans are going to react."

Fans began voicing their concern when Rhimes recently tweeted a quote from author Kurt Vonnegut: "Be a Sadist. No matter how sweet and innocent your leading characters, make awful things happen to them — in order that the reader may see what they are made of." Yikes! The ominous quote, Rhimes says, was just what she needed to give her "the courage to do what we're doing in the finale."

The heart-stopping drama begins in the May 10 episode with "a big case that takes a group of our people out of the hospital. It's sort of the medical case of their lives," says Rhimes, hinting that the patient could possibly be one of their own.

That episode will also give us our first glimpse of Derek and Meredith's completed dream house. While Rhimes originally planned for the season to end with the couple watching in horror as their new home burned to the ground, she says, "I was not ready to do that."

Instead, the dream house is being constructed and is "quite beautiful. I feel like this is the moment for it, since Meredith and Derek are having a debate about their future. I just hope we can use it next season."

While she's keeping much of the finale secret, Rhimes does offer a few specifics. Fans can look forward to some "extraordinarily romantic Ben and Dr. Bailey stuff," with Bailey making a decision "that will fundamentally change her life."

And keenly aware that "Mark and Lexie fans have been very adamant about them getting back together, they'll have some very beautiful moments with one another that I hope the fans are going to really love," Rhimes says.

Cristina will continue to struggle with the fact that she is "a gifted, talented surgeon first, before being Owen's wife," while Alex will struggle with a decision he's made. Adds, Rhimes, "We watch Alex have a really lovely moment where we discover how much he's grown up this season."

Curiously, Rhimes said there was nothing she could reveal about Callie and Arizona's storyline in the finale, which frankly has me worried.

And what of Meredith and Derek's future? After repeatedly saying she didn't know the status of Ellen Pompeo and Patrick Dempsey's contracts for next season, Rhimes now says she's not allowed to discuss the matter. And by the end of the finale, viewers may still not be entirely clear as to who will and won't return.

"We sort of end with our breaths held," she teases. "It's a great moment. We were joking in the writers' room that if this was the series finale we'd be good to go. But we've been told very clearly it's not."

Did Rhimes have to write one of the "nightmare scenarios" she told me about a year ago, should she lose one of her core actors? "This was born out of a nightmare scenario," she confirms, but then it turned out "to not necessarily be the nightmare scenario that I thought it was going to have to be."

Rhimes' hope is that the outcome of the actors' contracts will remain secret until the finale airs. And she does offer one bit of encouragement. After killing off T.R. Knight's George in 2009, she believes "there are certain characters on this show that you can't kill. It wouldn't be acceptable not only to the audience, but to me and my vision of what this show is. They can't die."

Yet, at least one will soon be eulogized. "The lives of our people should be a concern," Rhimes says. "A lot of choices are made in this episode that change people's futures forever."

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