Let’s reword the situation:
On the morning of 14 February the M/V Douglas suffered a casualty. A fire formed in a passenger lounge. While personnel attempted to evacuate the space the fire suppression system failed to operate as expected resulting in increased fatalities. This model of fire suppression system is known to fail frequently. Despite this knowledge the company did not increase maintenance and upkeep, and regularities bodies did not require a back-up system. Cost was cited as a primary reason for forgoing upkeep and redundancy.
As written above it’s easier to see where the system failed.