"1/4 of the time people who needed emergency responders had to wait because they were busy looking into false alarms." That would be even better, as that would

"1/4 of the time people who needed emergency responders had to wait because they were busy looking into false alarms." That would be even better, as that would mean 3/4 of the alarms are hits/non false-positives. I argue that even a 1/4 hit rate, i.e. 3/4 false positive rate, is a good start.