Jordana Brewster as Cahill
Murtaugh (Damon Wayans) and Riggs (Clayne Crawford) discover a hidden scheme while investigating the murder of one of Cahill’s (Jordana Brewster) patients in Season 2, episode 13 of Fox’s “Lethal Weapon.” Fox/Michael Desmond

Cahill loses one of her patients in the next episode of “Lethal Weapon.”

According to the synopsis for Season 2, episode 13 of the Fox series, an escaped patient of Cahill’s (Jordana Brewster), who mysteriously goes off the rails, is murdered. Murtaugh (Damon Wayans) and Riggs (Clayne Crawford) investigate the killing and discover that the poor patient is a victim of a hidden scheme far bigger than they imagined.

Meanwhile, Riggs’ anger gets the better of him once again, causing Avery (Kevin Rahm) to consider whether or not he is fit to serve. In the trailer for the episode, Riggs appears to be more short-tempered than the usual. In a scene from the episode, Riggs is getting in his truck when he accidentally dings the car parked beside his vehicle. The driver of the car confronts Riggs. But instead of asking for an apology, Riggs intentionally hits the man’s car with his truck on his way out of the parking lot.

“Would you say that I’m more angry or less angry?” Riggs asks his partner in the trailer. “There’s no wrong answer.”

When Murtaugh replies that he thinks Riggs is “more angry,” the latter gets offended and hits him in the shoulder. The father-of-three is taken aback and reminds Riggs, “You said that there was no such thing as wrong.”

Riggs says that he lied, and claims that he’s now better because his “old him” would have flipped out when he heard Murtaugh’s answer.

Also in the episode, family tension runs high between Murtaugh and Trish (Keesha Sharp), as the two try to make big decisions about their son RJ (Dante Brown).

The episode also marks the acting debut of NASCAR driver Matt DiBenedetto. In a video he posted on Facebook last November, DiBenedetto opened up about how he got the gig and what it was like filming his scene.

“I got a phone call asking if I would fly out here in Los Angeles and be in a scene in the TV series ‘Lethal Weapon’ on Fox. And of course, I was like, ‘Heck yeah, I’ll do that.’ So they hooked me up,” DiBenedetto says. “Everybody knows I’m comfortable being on camera, but acting and being part of a TV show is crazy. I have a whole new respect for what those guys do. It’s really really tough. It’s amazing to see what all detail goes into just creating just one scene. It was one of the coolest experiences I’ve got to do.”

“Lethal Weapon” Season 2, episode 13, titled “Better Living Through Chemistry,” airs on Tuesday, Jan. 16 at 8 p.m. EST on Fox.