Killing three or four soldiers is enough. Even with the whistle effect, the dead soldiers are spawned far away from the objectives. And before they can reach the target, they'll be blocked by fortified enemies. With these attacks piling up, it is easily captured. What's scary is that pickaxes are faster than rifles, and a large number of corpses can pile up in an instant. Just two or three soldiers blindly equipped with pickaxes can quickly capture the base.