|Avoid and use cover.
The Sentry Gun is a trap found throughout the Tomb Raider Games.
Tomb Raider III
The Sentry Gun first appears in Tomb Raider III. They are used in Nevada to protect the Military Base. These turrets are ceiling or wall mounted. They are triggered by Lara walking into lasers, shooting at it or manually by a member of the Military Police that has spotted the intruder. After it's been triggered, the turret will start shooting once Lara is in the gun's range. Some sentry guns can be turned off by a switch.
Tomb Raider IV: The Last Revelation
In Tomb Raider IV: The Last Revelation Lara comes to Cairo where the SAS have set up Sentry Gun traps. These sentry guns have a sensor that recognises when a target is in front of them. They cannot spot a target behind them. If the sentry gun recognises a target in front it starts its automated machine guns. If the target it close, it will switch to a flame thrower. The sentry gun can be destroyed by shooting at a red marking on its tank, probably loaded with whatever it uses to fuel the flame thrower. It will explode.
Tomb Raider Chronicles
Lara Croft Tomb Raider: The Angel of Darkness
In Lara Croft Tomb Raider: The Angel of Darkness there are ceiling-mounted Sentry Guns in the Strahov Fortress. They will start firing if Lara climbs down from walkways located higher in the area. Lara climb to a control room where she can use a magnetic crane to destroy the turrets. Another occasions when Sentry Gun are encountered are in the Aquatic Research Area. There the Sentry Guns are first tricked by releasing clouds of steam, and the second time they're destroyed by causing an explosion.
Lara Croft Tomb Raider: Legend
In Lara Croft Tomb Raider: Legend Lara will find a gun turret in the penthouse of Shogo Takamoto. The gun will only shoot Lara while she touches the lasers placed in front of it. Lara can do nothing but shield herself by using a giant movable ball.
Lara shielding herself from the turret in Tomb Raider Legend
Ceiling-mounted Sentry Guns in Strahov Fortress
Sentry Gun tricked with steam in Aquatic Research Area