Exclusive NCIS: LA Sneak Peek: Kensi and Deeks Have Their First Fight!

Are Kensi (Daniela Ruah) and Deeks (Eric Christian Olsen) moving too fast on NCIS: Los Angeles?

Since agreeing to go all-in with their relationship a few episodes ago, the couple have been moving full speed ahead - but a "post-wakeup argument" on Monday's episode leaves Kensi perhaps wanting to put the brakes on.

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"They wake up together and they're super cuddly, and on a turn of a dime she gets really offended about something and he doesn't know where it came from," Ruah told TVGuide.com during a recent set visit. "I think it's really well-written in the sense that I understood both parts. It's one of those arguments where the stereotype man and the stereotype woman are in completely different playing fields in what they're talking about. In this case, Kensi is kind of offended about something that he says. And to him it's like, 'Why would you ever be offended by that? It's really no big deal. ... You were just kissing the back of my neck. How did we get here right now?'"

Unfortunately, that's not the only fight they'll deal with in Monday's episode. A work-related crisis forces Densi to table their argument to deal with more pressing matters. In a callback to the Season 5 episode "Frozen Lake," the episode marks the return of the Nepalese Gurkha Thapa (Ernie Reyes Jr.), who the crew enlists for help after Sam (LL Cool J) is shot while trying to apprehend a spy. But, in the course of their investigation, Thapa and the NCIS team begin to suspect that his own country may be working against him. which leads to Deeks and Kensi squaring off with a slew of knife-fighters in a hospital corridor.

"It's kind of a race to find the truth in the midst of trying to keep Sam alive, and trying to keep Kensi alive, and trying to navigate a relationship," Olsen notes. "It doesn't stop."

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Ruah worked with the episode's writer, Dave Kalstein, to choreograph the hospital fight scene based on martial arts and the Filipino knife-fighting technique known as Sayoc Kali. "I'm very meticulous when it comes to fight scenes," she says. "It's one of my favorite things to do on the show. And I do have a dance background, so I think of everything as a choreography with beats. ... My body knows the dance alphabet. So when they tell me to spell a certain word, I know how to do that. Even though it's a fight versus a dance."

So how does this particular fight scene stack up against other ones Ruah has performed on the show? "In terms of moves, I think this is probably the hardest that I've done," she says. "Because it's also a very specific type of fighting. It's not like you're just throwing punches or something like that. It's a specific type of fighting and you want to be as faithful as you can to the technique of it. I'm not perfect or anything like that. And then there's also the fact that I just want to look tough."

For Deeks, who at one point finds himself on the other side of a hospital door, watching Kensi and Thapa tussle with the other Gurkhas, it's a new dynamic. "The stakes are so much higher because of the fact that he's in love with her," Olsen says. "So, it's that delicate balance of trying to stay alive while trying to do justice to that love."

Check out an exclusive clip of Monday's episode above.

NCIS: LA airs Mondays at 10/9c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)