Brother for brother

A soldier in a gas mask and camouflage crouches behind a train track, aims a scoped rifle, and fires, with the spent cartridge ejecting; the scene cuts to the soldier standing in a dilapidated building, then back to the soldier firing, followed by a shot of two soldiers on a platform with one falling backward in a spray of blood. The setting is a desolate, post-industrial landscape with train tracks, power lines, and abandoned buildings under a cloudy sky.