Miserable happening at a self-service gas station

It seems that self who did not understand selfish type gas station stuck a button for fire, the stand was badly extinguished with fire extinguishing agent. When it calms down, it is completely white around the area and it looks like a snowy country.

Details are as below. Exquisite white with extinguishing agent.
YouTube - Water Explosion at Gas Station


I think that if it is such a button that the fire extinguisher comes out so loudly, I think that measures are taken usually not to be pressed easily, but why has it become such a thing?