It looks like videographer Pascal Marchand was close when this alarm was dispatched around 7:30 PM Wednesday on Île-de-France Street in Longueuil, Quebec. According to news reports the structure is a triplex.
At 2:22 in the video a pair of firefighters take turns throwing bricks (or possibly another item) at the building. I am not sure if this was an attempt at ventilation or maybe just a firefighter ritual in Canada I am unaware of. Possibly it is just a way to keep warm with the temperature at the time of the fire at minus-32 degrees Celsius.