Looks cool, but I would be worried about mistaking it for a flare or, worse, mistaking a flare for the extinguisher, in a panicked emergency. The old style fire extinguisher is easily recognizeable.
The mental picture you painted of setting off a flare to put out a fire had me rolling. LOL
Safety First!
Those Ports similar to what you are using are also installed on boat engine covers to allow you to discharge a fire extinguisher into the engine compartment.
Speaking of discharge:
In a Trade shop building at a Job Corps center, A new instructor was opening up, preparing to start a new day. Upon entering, a strange pale yellow powdery substance was found inside, covering everything with a thin coating of fine dust. WTF? Security!
As we went in, snickers ensued as the huge empty fire extinguisher was discovered.
Nice one...
Gotta love those Kids!
Teach your Children well.