Man Shoots Family Right Before Evil Dissipates

by Avery
(Sunrise, Florida, USA)

What is the name of the horror movie where the final scene shows a man with his family in a car when they think the (unknown evil) is coming and they decide he should shoot them first before it gets them?

He then shoots everyone including his son and runs out of bullets and can't shoot himself. Moments later the sound he thought was the (unknown evil) turns out to be military personnel there to save them.