As already stated, fire extinguishers are only ever good for a "one shot attempt" on a very small fire in the early stages of the combustion process.
Only attempt extinguishment when you have bullet proof avenue of escape !
And remember the 3 P's
Pull (Pin)
Point (at base of fire)
Press (handle)
I once attended a shed fire where the occupant pulled the pin on the extingiusher and then threw it like a grenade into the fire
He thought thats how they worked