For several years, David Bassom has been compiling the "stories behind the stories" of Battlestar Galactica in his successful series of Official Companions. His books are an entertaining and insightful read, mixing recaps, behind-the-scenes anecdotes, glossy photos, and countless interviews.

Unlike the second Companion, the third volume does not feature a dedicated interview with Luciana. However, she is allowed to speak her mind on the bittersweetness of her last episode, "The Passage", in the respective chapter of the book. Among other things, she shares the strange story of how she found out about Kat's death.
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Transcript of the book section

[Jane] Espenson's script ["The Passage"] was assigned to director Michael Nankin, who had previously helmed the pivotal Kat episode "Scar". Unfortunately, by the time the script was distributed to the series' cast and crew, neither [Ronald D.] Moore nor David Eick had managed to warn Luciana Carro about her character's demise. "I had no idea that was coming," Carro confirms. "I only found out about Kat's death from my roommate!"

"I was flying from Los Angeles to Vancouver to shoot 'Unfinished Business' [3.09] when my roommate called me to say she'd got the script for 'The Passage' and that it was centred around my character. She was so excited about my role and all the information that was coming out about Kat's background.

When I heard about that I said, 'Can you do me a favour? Can you check the last page and see what it says ' And she said, 'Oh no... They've put Kat's picture on the Memorial Wall!' I was like 'What?!' I couldn't believe it. So I was there in the airport, crying. It wasn't the ideal way to find out, but these things happen."

"I do still feel bad about the way Luciana found out," Moore admits. "It was every producer's nightmare come true!" Fortunately, once the initial shock of her character's demise had passed, Carro was thrilled by the way "The Passage" allowed her character to bow out of the series.

"I thought the episode was great," she states. "It gives Kat a very heroic send-off and it really explains a lot of things about her – why she had issues with authority and why she was always trying to prove herself. Kat always wanted to prove that she was a good person, and she does it in that episode. I thought that was great."

"Obviously, I would have preferred not to have been killed off," she notes. "I do feel there was a lot more they could have done with Kat. But I completely understand why they did it and my death scene was really great. I'd always wanted to do a scene like that with Eddie, where Adama is like Kat's father. That was actually the last scene I shot and it was very emotional."

"I was surprised by just how strongly the crew was affected by Kat's death," she adds. "When we were shooting the episode, several crewmembers tried to rewrite the ending to keep Kat's fate open. They suggested she was a Cylon, or a spirit guide, or something. They would give me these new pages of the script and I would be like, 'Don't give them to me, give them to Ron!'" she laughs.

As painful as it was for the cast and crew, Kat's heroic demise helped make "The Passage" a strong instalment of season three. "I like 'The Passage' a lot," says Moore. "It's one of the most harrowing episodes we've done and I think the revelations about Kat are really interesting."

(David Bassom's Battlestar Galactica – The Official Companion: Season Three, chapter on "The Passage", page 67)