In the mission "Cairo Station," you must sever three cables anchoring the MAC gun to prevent the Covenant firing it at Earth.
Method
Weapon: **Brute Shot** (grenade launcher) — found on dead Brute at encounter start. 1-2 shots per cable. Battle Rifle / SMG work but take a full mag each.
Targets: Three thick cables on the central column. Glow faintly; reticle locks on.
Order: Any. Each snaps after ~2 Brute Shot rounds.
Cover: Fight from crates/structure. Drones & Brutes flank. Brute Shot melee for close quarters.