From Halopedia, the Halo wiki
Scurty Bump is an achievement in Halo: The Master Chief Collection. It is unlocked by beating the 15-minute par time on Keyes. The achievement is worth 10 Gamerscore and can be unlocked on any difficulty.
The achievement is named after speedrunner Scurty. The "bump" is most likely referring to the "Flood Bump" technique, which makes use of a reviving combat form to bump through the dislodged wall at the very beginning of the level. It may also refer to the older "shield bump" technique, which uses the Covenant portable shield farther down to bump through the walls and get into the bridge of the ship.