Wait, How'd the Ship Get Down Here?
From Halopedia, the Halo wiki
Wait, How'd the Ship Get Down Here? is an achievement in Halo: The Master Chief Collection. It is worth 10 gamerscore. It is awarded by beating the 20 minute par time on The Pillar of Autumn in Halo: Reach.
The name of the achievement may likely be a reference on how the UNSC Pillar of Autumn was previously stated as a non-atmospheric spacecraft, and thus shouldn't be able to initiate drydock on the surface of Reach. The name could also be a reference on how the events of the campaign level has retconned the events of Halo: The Fall of Reach. According to the novel, the vessel is said to jump away from Epsilon Eridani system at 0647 hours. However, its appearance in the level, which takes place at 1652 hours, suggests that the ship has remained in the system after its supposed jump. When the game was first released, these two points were commonly raised by community members as criticisms on how Halo: Reach contradicted previously-established fiction.