Instead of spraying out extinguishing agents at a fire, the Vacuum Extinguish Method (VEM) sucks the flames and burning materials into a vacuum chamber, where they can be safely suffocated or extinguished.
Fire is one of the most frightening emergencies that can happen aboard a manned spacecraft, submarine, or other enclosed, special environments. Not only can one be about as deadly as a fire can get, but combating it is extremely difficult, not only because of the heat and smoke given off, but because the extinguishing agents can be almost as dangerous in an enclosed space.
This is the reason why firefighting teams aboard submarines and the International Space Station need to don oxygen masks before dealing with the fire. Even if the agent used is as innocuous as carbon dioxide, the crew can still suffocate without breathing apparatus. Even water in a weightless environment can be hazardous.