Declaring an emergency is a standard method employed by humans to let other humans know that they think there is an emergency that everybody should be acting on.

If I see a fire in the house I am in, it might be in the grate, or it might be on the sofa. If I declare some sort of 'fire emergency', it can help to point out to other humans which of the two situations I think I am encountering and how they might therefore choose to react.

I hope this helps.