我一開始還以為是什麼射擊
進來之後才發現我誤會了

順便去找了Final protective fire的解釋



http://en.wikipedia.org/wiki/Final_protective_fire

Final protective fire (or Danger Close) refers to a tactical plan for a military unit, typically infantry, to protect itself in defense against attack. The plan generally includes machine gun, mortar, and artillery fire prearranged to impede enemy movement across defensive lines or areas.

As the "final" in the name implies, it is the last resort in defensive plans, normally involving artillery and/or heavy machine gun fire directed dangerously close to friendly defensive positions that are at risk of being overrun by the enemy. A request for final protective fire generally has absolute priority over any other kind of requests.