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)
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-..).
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)
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)
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).
Continuity mistake: One of the protesters approaches Chief Boden twice.
Continuity mistake: When Ritter pulls up to the overpass, the car's lights are on. They are off in the next shot when he exits the car and on again in the next shot as he walks away from it.
Escape Route - S9-E8
Continuity mistake: When Casey is in Molly's bar, Stella places a beer down in front of him. The level and amount of foam changes several times throughout the scene before Casey brings the glass to his lips.
Continuity mistake: Herman dumps coins on the map and as they explain how to use them, the spread of coins changes and there is a pile of coins that wasn't there before. (00:26:36)
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 ★