It s part of the responsibility one takes when stepping to the helm. Boats are not like cars, you have to be familiar with the systems and upping loosing power on both engines, as well as generator and blowers, flipping the override switch should be instinctive after verifying that there is no actual fire
The risks of loosing power at a critical time are far lower than the engines sucking in the extinguishing agent in a fire.
In 30 years I be never seen one these boxes fail
But unfortunately when the engines are in the same compartment, you don’t have any option
I installed a new Fireboy system on my 53 which has split engine rooms and the gen in another compartment. I have 3 bottles, one in each compartment and instead of using 3 shutdown boxes to keep the redundancy, I setup my own using basic relays override switches and the FB indicators. Been working very well so far.