I wonder what type of extinguisher was used as they can be deadly.
CO2 fire extinguishers spray dry ice, essentially. If you get it right on your skin it can freeze burn you, not to mention triggering asthama from other extinguisher types designed to smother a fire by removing the air.
Higher concentrations, like you might be exposed to when sprayed by a fire extinguisher, can affect respiratory functioning. In addition, high concentrations of CO2 can cause the central nervous system to be simultaneously stimulated and depressed, a phenomena that can have dangerous results even death.

Also I am sure the extinguishers on scene were required by The Bda Fire Services Fire Prevention Department as a safety item for this event in case of an electrical fire.
Now we have another thing for the kids/youth/adults to UNlearn, and that is a fire extinguisher is NOT a fun toy or stage prop to be played with.
Don’t be surprised if the extinguisher’s in schools suddenly become popular play things after they view that video posting.
Submitted as a 30 yr veteran Bda Fire fighter.