Other mistake: In the pilot, Heather Darden states that Andy had been at the house for 14 years. Assuming that he was placed there directly after the Academy that would place his age at 32 years old at the time of his death (2012). In Season 3 (I Am the Apocalypse), April Sexton gives her year of birth as 1982, making her 33 years old in 2015. April and Andy both are said to be the same age as Kelly Severide, as Darden went to kindergarten with him and April sat next to them in class, however there is at least a 3 year age difference between Andy and April.
Continuity mistake: While at the Firehouse and talking about Dawson getting Candidate EMT Tara "tanked", they have pancakes and sausage and as Otis sits, his sausage is on top of his pancakes and then when Casey walks up the sausage is cut up on the side. Then when it goes back to Otis the sausage reappears back on top of the pancakes, untouched. (00:28:28)
Character mistake: In the first call to a working structure fire Severide proceeded to head towards the basement from the middle level by walking down stairs but falls through. His first mistake was not checking the stairs with the halligan as any firefighter is taught, to check if they are sturdy. And last but definitely not least no firefighter should ever walk down stairs, especially wooden framed ones if they are on fire.
Continuity mistake: No snow in all exterior scenes except for when Chief Bowden pays a return visit to have dinner with the female resident of the building which was a fire scene early in the episode. He gets out of his car and walks to the building with several inches of snow on the ground. The immediate next scene of Shay (supposedly the same time) has spotlessly clean streets.
Continuity mistake: When Jeff Clarke comes by the firehouse, Hermann wants to hug him but Clarke says "I don't really like people touching me." But throughout season 2 Clarke has hugged other fellow firefigthers (Cruz among others) with no problem.
Apologies Are Dangerous - S3-E4
Continuity mistake: When driving to their first call that shift (guy stuck between cars), Truck 81 is seen arriving at the scene while it should be still being repaired. When they arrive back at the firehouse, the truck they drive carries the number of the exchange truck they've got (E-..).
Revealing mistake: In the scene on the roof when Severide is removing the helicopter door with a spreader, there is no hydraulic pump or hoses attached, just the bare tool. When he sits the tool down you see this. So the spreader would not be working at all.
Continuity mistake: Brett enters the abandoned factory twice when she is searching for the missing girl.
Continuity mistake: At the hospital, when Cruz talks to Herrmann while he still has the oxygen mask on, Herrmann's hand keeps switching between clutching the mask on his face and resting at his side. (00:38:45)
Where the Collapse Started - S4-E22
Visible crew/equipment: After the paramedic locates the injured firefighter, the shot cuts to the outside and the camera operator's shoulder can be seen in the lower left of the shot.
Continuity mistake: When Dawson and the police detective are knocking the door of a suspect a neighbor is coming out to sidewalk and the snow is piled high along the sidewalk and parked cars. The next scene shows the ambulance and fire engine on the road with no trace of any snow. (00:44:00 - 00:47:00)
Continuity mistake: When Brett and Dawson go rescue the two climbers, at the very beginning you can see a long shot of the group where the victim is laying with her legs and arms straight, while in the rest of the scene she lies there haphazardly in consequence of the fall. (00:09:45)
Continuity mistake: Casey and Kelly are on the roof smoking cigars when a man runs up carrying his daughter yelling for help. Both Casey and Kelly put down their cigars and are next seen sliding down a ladder with black gloves on. They were not smoking cigars wearing gloves, and wouldn't have time to put them on to get off the roof as fast as they did. (00:21:00)
Continuity mistake: Chief Boden is in his dress uniform and his award ribbons above his right pocket are hanging down. There is an emergency and he orders the firefighters to mount up to depart the firehouse. They all leave in a hurry, and when Chief Boden arrives on the scene his ribbons are no longer hanging from his jacket, but intact and straight above his right pocket. (00:41:00 - 00:43:00)
Other mistake: Captain Casey has Lieutenant pins on his uniform instead of Captain pins. (00:31:00)
Factual error: In the scene at O'Hara airport the paramedics meetup with a TSA officer. The TSA officer has a gun as a part of his uniform. TSA officers do not carry firearms. In addition, the CBP officer in the scene does not have on a proper CBP uniform. The CBP officer uniform has rank epaulets and officer has no epaulets, and the CBP uniform doesn't have a bar tie clip and the gun belt buckle is brass not stainless metal. (00:42:00)
No Such Thing as Bad Luck - S7-E18
Character mistake: At the formal awards ceremony for Cruz the Police officers and Cruz are in dress uniform with their covers on. Serveride joins them on stage in uniform without his cover on and salutes Cruz. Serveride should have known to have on his cover for the ceremony. (00:58:00)
Continuity mistake: The entire fire house is in the hospital waiting room for word on Otis. Chief Boden sits down twice next to Casey.
A Real Shot in the Arm - S8-E2
Continuity mistake: When Sylvie and her ex hometown friend are having milkshakes, both milkshakes keeps switching back and forth between full with whipped cream and a cherry (when Sylvie is in view) and partially full with melted whipped cream and no cherry visible (when her friend is in view). (00:20:00)
Continuity mistake: Casey and Seagar run down the stairs leading to the parking garage. Seagar passes the 15th floor twice (large sign on the wall).
Answer: Internet sources give many reasons why firefighters do this, but in regards to your question, it's probably because opening walls and ceilings creates better ventilation which allows heat and smoke to escape, giving firefighters better visibility and lowering the temperature.
raywest ★