One For the Record Books
From Halopedia, the Halo wiki
Unlike most other par time achievements, this achievement is affected by a great deal of luck due to the level consisting of a number of randomized encounters. Although the three main objectives ostensibly take the same amount of time each playthrough, the secondary objectives vary in time and location. While most are relatively brief, others, most notably escorting Gunnery Sergeant Edward Buck, take significantly more time. Their placement on the map is also random, so an unlucky player may have to backtrack and do extra flying around the map to complete the objectives.
- The name of the achievement may be a reference to the Library of Alexandria.