Losing her friend a few weeks back has put Lindsay (Sophia Bush) right back on a destructive path when it comes to what she'll do with her life, but that decision is going to prove to be a dangerous one on the season finale of Chicago P.D.

Lindsay 'Spirals' Out Of Control

Following Nadia's death at the hands of a twisted serial killer, Lindsay has spiraled right back into the dark places and has fallen back into the comfort of her old demons--the same ones Voight (Jason Beghe) rescued her from when she joined the force.

"So you're back to your old habits," he says to her in a preview clip for the Wednesday, May 20 finale.

The Cross-Over Gets Personal

Now, those habits could haunt her--and may even cost Lindsay her career after she makes a horrible mistake while on a call.

"As she spirals out of control, she'll make the ultimate mistake," a voiceover warns in the clip.

Sure enough, when Lindsay gets to the scene of what's going on, she appears to aim her gun at a fellow officer--and then pulls the trigger, bringing panic to her friends and co-workers after they arrive on the scene--with Dawson (Jon Seda) and Halstead (Jesse Lee Soffer) looking particularly shocked by her actions.

Now, everyone will need to figure out how to cope with this drastically and dramatically changed version of Lindsay--and she will need to decide once and for all if she is really cut out for the police department after all.

Chicago P.D. airs Wednesdays at 10 p.m. on NBC.

Tags: Chicago PD nbc television