Violet insists that she and Carver are extraordinarily casual to nth degree while they're actively engaging in hanky panky.

Hermann and Mouch get Tony with a wayward faucet.

Kidd teases Violet about her thing with Carver.

Violet cannot believe Lennox is there again, and she finds Severide and Boden discussing him. They cannot believe he had the nerve to show his face again, and Violet isn't keen on working with someone who scrutinizes her every move.

Gibson called off for two shifts, but he says he's feeling better now.

When traffic gets snarled, he overreacts, causing Kidd and Carver to raise their eyebrows.

They've been called to a dialysis center where a woman has passed out. Violet notes the pulse is weak, and she needs oxygen. Others begin to cough and collapse, and Stella wonders if it's due to the dialysis. Uh oh, there's smoke coming out from under a closed door.

It's a hazmat situation, and they need level-one hazmat and many more stretchers.

Stella finds a guy she knows, Charlie, and helps him out.

Hazmat gave a ten-minute ETA, but Severide thinks they need to get in there now.

Disinfectant might be reacting with bleach to cause the situation. Cruz and Severide try moving a massive can to stop the leak. Mission accomplished.

Everyone wants to prank Lennox, but Severide tells them absolutely not to do it.

Kidd, Carver, and Mouch visit Charlie to see if he's OK after the incident. He doesn't answer quickly, and they see him on the floor. He's got a puncture wound on his wrist that is spurting blood.

They take him to Chicago Med, where it's determined that his fistula exploded due to over-exertion.

A fellow named Keith congratulates Boden for being on the DC shortlist. He may suspect that Robinson's trying to sabotage his chances. He needs to have a face-to-face with Robinson.

Carver asks Gibson if he's OK. He invites Gibson to a dive bar they visited a couple of weeks back. Gibson is in.

She disagrees that her charges were unnecessary. She also called Violet aggressive and confrontational. She is doubling down on this garbage. She's trash.

He assures her that she's not going to get to the top alone. He offers his full support if she drops them.

Gibson never shows, so Carver drinks alone.

Gibson hooked up with a girl from the hospital. He's apparently seeking drugs under the guise of losing his past prescription.

Stella and Kelly bump into each other at home, which allows them some time to get it on. They're interrupted when Stella gets a call about Charlie.

His kidneys are functioning perfectly. The initial assessment might have been wrong, but even worse, he may have been misled.

Robinson won't drop the charges. Boden gives Severide the news, and Severide says that taking it up the chain of command will only put Boden's job in jeopardy.

Stella is researching Charlie's doctor to see how this happened.

Mouch requested eggs without yokes. They're all yukking it up when Lennox enters the room, and they silence themselves.

Gibson doesn't care and shows Lennox what it means to be aggressive.

Boden walks through the room and notices Lennox all alone and the utter silence.

Ambo gets a call. It's at a bar when a fellow fell on his shoulder. The result is that a bone is sticking out through his neck. Eddie doesn't want his jacket cut, but getting it off without pain is a friggin' nightmare.

Violet gives the guy fentanyl and cuts along the seams of his jacket. Lennox doesn't want to sit in the back. She says PIC drives and wonders if he's asking her to break it. He is and has excuses about it.

Boden visits DC Hill. He lets her know that Robinson isn't a suitable candidate to fill her shoes. Hill thinks Robinson is a great candidate, despite Boden's pleas otherwise. He doesn't want the entire CFD to be filled with distrust and disunity. Hill doesn't care.

The urgent care doctor who diagnosed Charlie has terrible reviews. Violet says that the clinic will put up roadblocks to prosecute him. But then Stella finds the doctor is also the CEO of the dialysis center. He's referring patients to himself.

Carver confronts Gibson's withdrawal. He gives him some tough love to pick himself up off the floor and pull himself together. Or what, Gibson wonders?

So, Gibson smashes his hand into the locker.

Boden calls Lennox to the office to tell him he's not a good fit at 51. His presence is doing the firehouse damage. Boden says he should reconsider helping Robinson because it doesn't look like she's got anything to lose while Lennox's career is stalled.

Stella follows a blood trail in the bathroom to find Gibson curled up in a shower stall. He says he needs to get out. He needs to go.

Stella talks to Severide about Gibson, and he assures her that hiding it is the name of the game. Boden was the best boss ever and he was the last to know about Kelly's addiction.

Not everyone is cut out for 51, he says. The Lennox situation shows that too.

The marshal Severide worked with at OFI is all in.

Violet is happy Lennox left but is worried about Boden getting dinged for it. She asks if Carver is sad Gibson is leaving. She tells him she'll be wearing sweatpants tonight.

The charges have been dropped. An assistant at AI called. They have no idea why they were dropped.

Herrmann gets in the car, and glitter sprays all over the place. Sorry, but that's dangerous.

Gibson thanks Carver for keeping it real with him.

Stella and Kelly are on hand at the clinic to do a full fire eval. They see plenty of offenses, and they'll be shutting him down and looking into his referrals.

Robinson plans on sticking around during the interim to make everyone's life a living hell.