More precisely, it said "After the strike never materialized, the sprawling installation's command post put out a notice stating that "the missile launch was then assessed to be part of a training exercise" and wasn't deemed a threat to the base"

> If you've sent an alert to the soldiers on the base, you've decided the warning is genuine

Or that you are checking. It may be a false alarm, in which case you will at least get a test of your readiness drills, which may find bugs in the process. Sometimes better to start getting ready while there is still time, and then stand down. Rather than wait until it is too late.