Shadow of the Tomb Raider

In the Main Menu, select the "Challenge Tombs" tab and then choose "Slayer's Gauntlet." In the following menu, you can then sift through three different modes: Exploration, Score Attack, and Time Attack.

In order to unlock this achievement, you will need to earn any medal in Time Attack. This mode is all about completing the Challenge Tomb (i.e. reaching the stele) as quickly as possible. The medal requirements are as follows:

• Gold: 8 minutes
• Silver: 10 minutes
• Bronze: 12 minutes

The Slayer's Gauntlet is a straightforward Challenge Tomb because there aren't any "real" puzzles; rather, all that's involved is opening gates in order to move through the area (avoiding traps along the way) and some light platforming sections. That being said, if you feel the need to fall back on a video walkthrough to get it done, please refer to THIS VIDEO, courtesy of KyoKat.