'Chicago P.D.' Sneak Peek: Antonio Dawson Reaches New Lows With His Pill Addiction (Exclusive)

ET exclusively debuts a first look from Wednesday's fall finale.

Detective Antonio Dawson is reaching new lows.

On Wednesday's fall finale of Chicago P.D., tilted "Descent," Dawson's (Jon Seda) addiction to pain pills starts to catch up to him and in ET's exclusive sneak peek, desperate times call for desperate measures.

In the clip, Dawson pleads with his doctor to write him a new prescription for oxycodone, the pain pill he's been taking well after his shoulder injury he suffered earlier this year healed.

"When you say pain, what type of discomfort are you experiencing: stiffness? Soreness?" the doctor asks, prompting Dawson to quickly answer with "I don't know... pain?"

When the doc declines to refill the script, telling him he probably needs some more rest, Dawson tries Plan B -- to no avail. "I need something to help me with the pain," he tries to explain.

"It's been three months since your injury, there's been no structural damage," the doc says.

"It's the only thing that helps with the pain," Dawson responds. But the doctor isn't budging, politely telling him four refills of oxycodone is a lot for his type of injury. Dawson snaps as a result.

"I'm not some type of junkie looking to hustle my doc for some pills!" he yells. "I'm a cop! I just need help with the pain so I can do my job."

Dawson's efforts to feed his pain pill addiction, which may put the Chicago P.D. team in trouble, are unsuccessful as he storms out of the doctor's office and proceeds to desperately search his bathroom drawer, hoping to find one last pill. Watch the exclusive sneak peek above to see what happens next.

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