"We were all on the way out here just talking (about how) it is hard to go and pimp your movie on a day like this, when the nation is sort of coming together," said one of the movie's writer-producers, Damon Lindelof.
"My cousin ran the Boston Marathon today. He finished half an hour before the explosions went off," he said. "So, I'm just relieved that he's OK. And I'm praying, and my thoughts are with the families of people that were injured or hurt in any way by this horrible thing."
Lindelof's longtime collaborator, "Star Trek" series writer-producer-director J.J. Abrams, stayed back in Los Angeles to work on the sound mix of the film.
But a number of film's actors made it to Sin City for the convention: Chris Pine (who plays Captain Kirk), Zachary Quinto (Spock), series newcomer Alice Eve (Dr. Carol Marcus) and John Cho (Sulu).
Like Lindelof, Cho had mixed feelings about hyping a movie on the same day as a national tragedy.
"This is part of the job for us," Cho explained. "(But) it was a weird feeling. I'm just going to say that. It's so sobering."
Perhaps one reason is that, like the Boston bombings, "Star Trek Into Darkness" is propelled by a terrorist. The story pits Kirk against John Harrison (portrayed by "Sherlock" actor Benedict Cumberbatch), a one-time top Starfleet agent, who threatens the survival of both Earth and Kirk's Enterprise crew.
"Terrorism is a huge part of our lives," noted Pine, "and we all know the effects of that."
For Quinto, the Boston bombings struck even closer to home. He recently completed a theatrical production of "The Glass Menagerie" there.
"I mean, I just lived in Boston the last three months," Quinto said. "I was horrified. It's just unfathomable. It's an amazing city and I know it's stronger than one tragedy like this. But it is certainly enough to set everybody back in an unfortunate and profound way."
"Star Trek Into Darkness" opens stateside May 17. CinemaCon runs through Thursday.
Follow Michael Cidoni Lennox at www.twitter.com/MikeCLennox