Boden knows how to get Dawson on a truck -- by keeping her at Firehouse 51. The catch is that Casey and Dawson cannot be married.

Mouch seems annoyed that Cruz didn't look at all the particulars, such as licensing, when he suggested they open a food truck for Molly's/

When 51 and 105 are racing toward a fire, neck in neck, Casey says he's not interested in a pissing match and tells Cruz to hold back. Except their trucks crash. WHAT?!

Mouch looks bad. He's bleeding terribly. Severide and Hermann are on the scene. Cruz is stuck. There are a whole lot of injuries on Welch's team.

Dawson and Brett arrive on the scene. Mouch can't see. Cruz doesn't know what happened. He says they came out of nowhere. Moments earlier they were parallel, then they were perpendicular. Only one of them made a turn.

The two firehouses are arguing. Welch's team says 81 blew the light.

Casey says "Dawson's taking him to Chicago Med." And I immediately remember the idea of a third part to this Chicago franchise.

Mills is working on the truck and he just plummets down the side of the truck to the pavement.

Cruz is taken aside by the police and given a breathalyzer.

The guy who is injured the most is Welch's best friend. If things were bad before between the houses, they're worse now.

Mouch has a lot of debris in his eye, but the injury didn't penetrate. He'll be fine.

Casey is assuring everyone that their feud played no role in the accident. He trusts that Cruz saw a red light.

Everyone from 51 moves out of the hospital. Severide is worried about Mills. Mills admits he's been getting dizzy since the building collapse and blames the pain meds. Severide says he should go to the hospital before next shift.

Boden calls in a whole new crew. His guys have been rattled.

Mills has major bruising on the side of his body. Boden understands Mills reached out to his dad's family. Boden told her he thought it would be a great idea. Dad always talked about his family, and wanted to patch things up. He wanted his children to know where they came from.

Dawson is very excited about being the candidate for Truck 81, but Casey doesn't tell her about the catch.

Casey and Cruz are called to a group meeting. They have a traffic cam from four blocks behind. Cruz blew through the light -- he called it a controlled stop. He could be looking at manslaughter charges.

Dawson and Casey talk about what working about means to their future.

Cruz is refusing legal counsel and makes a bad move at the hospital and feels bad about the accident. 

Hermann offers up Molly's to host a thing for Molina.

Severide is standing outside the hospital. He can't bring himself to go in.

Mills learns he has PVVB, and equilibrium problem. He can't be cleared to go back to truck.

Cruz' duties are suspended and Otis is now driving.

Severide looks for Mills. He's off squad. Severide is gutted.

Dawson goes to talk with Boden about how she and Casey are taking the opportunity seriously.

Newhouse wants a cut on the Molly's truck in return for giving them a truck.

Mills goes to see his grandfather. Leonard says Mills looks just like his mother.

Mills and Newhouse shoot some hoops and talk about Leonard and his ear problem. Newhouse thinks he's giving up too easily.

Dawson decides to tell everyone she and Casey are splitting up. I'm not sure why she does that. 

During the "thing" they get a call that Molina is awake and talking.

Molina comes clean. He told the Chief that Welch gave him the nod to get to the scene come hell or high water.

Casey tells the Chief they want Dawson on Truck 81 and Mills realizes there is an opening for a paramedic. He wants in.