the problem with venting is having crew in Vacc-suits when the fire starts. If it takes say as little as five minutes to get a suit on, sealed , and activated they may be working in a toxic soup of combustion by products, and near combustion temperatures.
even with a soft suit, or emergency suit the time to unpack the suit, get into it, and get your mask on is not exactly a speedy process. fire retardant undergarments, and face masks will protect the crewmen for a few minutes but in blinding smoke, intense heat, and a very high level of stress even trained crews have a hell of a time getting into protective gear.
My contention would be (and this is supported by some canonical sources, though I do not have the references off-hand), that the standard shipboard duty-uniform would either be a Tailored Vacc-suit (TL14/15), or the earlier TL10 Body Pressure Sleeve/Light-Duty Vacc Suit (LDV - which is form-fitting to the point of being able to be worn under clothing, or even a more substantial vacc-suit). And this, in my opinion, only makes sense since humans have been in space for 10000 years and have certainly had time to work out these problems. Therefore, the only thing that would need to be "put on" would be a pair of sealed gloves and a collapsible soft-helmet (and a small air-supply or oxygen-tube to a duty-station port).
This would simply be part of the discipline of the various space-services.
Possibly there is a fire suppression system that can afterward flood the area with cold CO2 to aid the cooling process.. . . once the fire is out, you have to wait for exposed surfaces to cool, and the source of initial ignition to cool down to point where it wont rekindle the second fresh o2 is introduced.