Turok 3: Shadow of Oblivion/Level 2: The Military Base

A military base located in the desert (presumed to be Area 51 or something similar). The player encounters military guards bent on stopping their progress. Later, after gaining a corridor keycard, the player encounters a wounded scientist who tells them the self-destruct sequence has been activated and the player must turn it off. When the player arrives underground, they encounter an aquatic life form that uses a weak long-range attack. The level's boss is called the Xiphias, a much larger version of the creatures the player encountered in the last few parts.