Is ‘Chicago Fire’ Putting Brett’s Job on the Line as Kara Killmer’s Exit Nears? (VIDEO)

Uh-oh, there’s trouble coming to Ambulance 61 in Chicago Fire‘s next episode, airing February 21, after a one-week break.

In “On the Hook,” Brett (Kara Killmer) and Violet’s (Hanako Greensmith) defibrillator malfunctions on a call, and they look for answers. The promo offers a look at just that. “There has to be an explanation for what went wrong,” Violet says.

Boden (Eamonn Walker) warns Brett, “if this is human error…” but she knows that, as Paramedic in Charge, “I’m on the hook.” (Violet will take over as PIC once Brett leaves.) Watch the full video above. But remember: Promos can be misleading, to surprise viewers with a twist.

But while Killmer is exiting this season, exactly when has yet to be revealed—”we have her for a bunch of the season,” executive producer Andrea Newman told TV Insider prior to the premiere—we doubt that she’s going to lose her job (or worse) before that. After all, there’s still a wedding to look forward to (and we doubt she’s going to be off the job for too long before then). Jesse Spencer is returning, and planning for the event is in full swing on the show. (Invites are now out!)

That being said, whatever happens in this upcoming episode could explain why Newman did tease that Brett’s plans “will not go exactly how she wants them to,” though she added, “Maybe it works out for the best, but it doesn’t work out exactly how she thinks it’s going to work out.”

Also coming up in this next episode, Herrmann (David Eigenberg) tries to find the perfect home for his new recliner, and a secret from Gibson’s (Rome Flynn) past comes to light.

Looking at Flynn’s character, the newest firefighter at 51, “The big question is always, when somebody starts at 51, are they 51 material? Are they troublemakers? Are they going to fit in? Or both? So it’s fun peeling back the layers on the Gibson character, and Rome is great,” Newman said. “We’re having a lot of fun with him right now.”

Chicago Fire, Wednesdays, 9/8c, NBC