On Tuesday's NCIS: Los Angeles, team psychologist Nate returned from his top-secret assignment, only to leave again by episode's end. Is he gone for good?

"I don't think this is the last you'll see of Nate," "It's kind of a big mystery. If there's not a bullet in my head, I'm not gone. It's left open-ended for some reason, and that adds to the mystery."

Cambor says he's been sworn to secrecy by executive producer Shane Brennan, who first pitched the storyline to Cambor last season. "I was like, 'Oh, that's different than what I thought it was going to be,' but I totally understand the reasons," Cambor says. "It's just part of the deal."

"It's a really exciting profession in the sense that you don't know what the next day's going to bring," he says. "It can be awesome, crazy, surprising and scary, but that's part of why I signed up to do this. In a strange way, being an NCIS agent is a microcosm for the entertainment business."