I'd say we just don't have enough information. It's possible someone deserves to be fired for this - e.g. if the alarm was intentional or negligent. It's also possible it was a misclick, confusing UI, etc, in which the person or people who should be fired are those who designed the system such that a simple mistake could set it off. There is a third possibility too - that some unpredictable alignment of factors means that ultimately nobody is too badly at fault, in which case the system should just be adapted and improved.
I generally agree with the sentiments of this thread - you shouldn't fire people for the kinds of mistakes that all humans frequently make. However, I also think that this was a severe and costly incident - a large number of people thought for a while they were in significant danger, and investigating who is responsible, and making corrections with regards to their employment, may be reasonable depending on the exact circumstances.