At the last event of this year’s PaleyFest Fall TV Previews at the Paley Center for Media, the cast and producers of CSI gathered Tuesday night in Los Angeles for a panel to say farewell to the groundbreaking series, which is ending its run after 15 seasons.

Though season 15 ended earlier this year, but the whole series is going out with a bang: It will conclude with a two-hour TV movie, which airs Sunday, Sept. 27, and reunites the current cast with beloved characters who already left the series.

The PaleyFest panel, which was moderated by EW’s own Lynette Rice, included creator and executive producer Anthony E. Zuiker; co-creators and executive producers Ann Donahue and Carol Mendelsohn; executive producers Jonathan Littman and Jerry Bruckheimer; William Petersen (Gil Grissom), who returns for the finale after having left the show; Jorja Fox (Sara Sidle); Marg Helgenberger (Catherine Willows), who returns for the finale; Ted Danson (D.B. Russell); Eric Szmanda (Greg Sanders); Paul Guilfoyle (Captain Jim Brass), who returns for the finale; Robert David Hall (Dr. Al Robbins); Jon Wellner (Henry Andrews); David Berman (David Phillips); Wallace Langham (David Hodges); and Elisabeth Harnois (Morgan Brody).

Here are five things we learned at the lively goodbye panel.

1. Anthony Zuiker delivers one hell of a pitch

“I think, if you’d all been there, you’d have hired him right away,” Bruckheimer said. “He gives the most energetic, entertaining pitch you’ve ever seen.” Littman said he called Nina Tassler — who has since parted ways with the network but at the time acted as executive vice president of drama series development at CBS — begging her to listen to their pitch after every other network had passed on the series.

“I said to Nina, ‘I don’t know if you’ll buy it,’” Littman recalled, “but I can guarantee you the most interesting 20 minutes you’ll ever have.” Tassler bought it in the room. Inside the elevator on their way out of the building, Zuiker remembers Littman saying to him, “She bought it in the room. That’s how you do it, my friend.”

2. This cast really loves each other …

Rice asked the cast to go in a circle and each share their first impression of the person sitting to their right. Their answers ranged from sincere to sarcastic, but all spoke with deep affection for the people sitting around them. Danson called Helgenberger “the most elegant, gracious, and welcoming lady that I’ve worked with” before Helgenberger told Petersen, “I can’t imagine taking this ride with anybody else.”

Fox said to Guilfoyle, completely seriously, “You have this New York sensibility, and this wit, and [you’re] down-to-earth, and you took risks, and you were just so classy, and kind of Austin Powers.” Guilfoyle broke the rules and replied to her, calling Fox “the heart of this whole group.” Berman revealed that he officiated Wellner’s wedding and threw his bachelor party, adding, “To get to work with my best friend every single day is pretty amazing.” Wellner paid it forward to Szmanda: “He’s so dreamy!”

3. … except Jorja Fox and William Petersen — at first

Fox sat to Petersen’s right, and when his turn came to recall their first meeting, he turned to her and said, “Did we meet at lunch?” Rather than answering the question, Fox replied, “You drove me crazy.” For the first how many months? “Like six. And then, I don’t know … I realized we were kind of stuck together.”

Petersen was not evidently bothered by Fox’s admission. He fondly recollected their first lunch together and said, “Every time I was able to do a scene with you, it was like falling off a log. I think that Grissom fell for you because you got him. And you got me, too.” The audience aww-ed, and Fox amended, “I adore you so much.”

4. Taylor Swift and Quentin Tarantino are both exactly how you would expect them to be

CSI has seen its fair share of fun celebrity guests (Justin Bieber comes to mind), but the two that came up during the panel were Taylor Swift and Tarantino. Swift brought boxes of CDs and told the cast and crew to bring their children to the set so she could sign a CD for any kid who wanted one. When one crew member’s daughter couldn’t come, Swift had him text his daughter a photo of Swift holding a handwritten “wish you were here” note. “I thought, ‘Oh, right, that’s why you’re a huge, huge star,’” Berman said.

Tarantino directed the season 5 finale, which Mendelsohn said was “one of the greatest experiences of all of our lives.” Tarantino co-wrote the episode, and Zuiker said, in fact, he broke the story in the room in the space of an hour. “He’s sitting there pitching, and next thing you know, stuff’s flying on the board, we’re like, ‘He’s breaking this thing right now,’ like Edward Scissorhands,” Zuiker explained, before launching into what seemed to be a fairly accurate impression of Quentin Tarantino breaking a story.

5. It is not appropriate for a crime scene investigator to say, ‘I’m sorry for your loss’

An audience member asked about how real-life crime scene investigator Elizabeth Devine became involved with the show. “We needed a CSI because we didn’t know what a CSI said when they got to the scene,” Donahue admitted. “Do you say ‘sorry for your loss’?”

She got in touch with Devine when they were working on a ripped-from-the-headlines plot about a quadruple murder. “Cops are storytellers,” Donahue said. “That’s their job; they have to get the story from people that are usually insane in that moment … and then tell it to their boss, who tell is to their boss, who tells it to their boss.”

Devine helped the CSI team nail down that crucial bit of dialogue. “You don’t say ‘I’m sorry for your loss,’” Donahue said. “You say, ‘Don’t touch anything; I need all five senses.’”

RELATED VIDEO: ‘C.S.I.’ finale teaser

The two-hour CSI finale airs on Sept. 27.

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