Sentinel launcher

Sentinel Launchers are small armor-covered devices built into the walls of some Forerunner facilities. When hostile entities, such as Flood, are detected in the immediate area, they open their cover and dispense Sentinels. One way to destroy a launcher is to attack it when the armored cover opens to release a Sentinel. It is also possible to destroy a closed dispenser by sticking a Plasma Grenade on its cover or meleeing it although this will cause your shields to become depleted. These launchers can be found in levels such as Quarantine Zone.