The Long Run
From Halopedia, the Halo wiki
The Long Run is the twenty-second track in Halo: Original Soundtrack.
The piece is almost entirely percussive, with a few synth sounds in the background, which seems to resemble the John-117 running. This makes it very similar to Drumrun. It consists of a repetitive drumroll which is designed to underscore the nature of the escape and to make the player feel a sense of urgency.
The soundtrack can be heard:
The track was arranged into Marathon Sprint in Halo: Combat Evolved Anniversary: Original Soundtrack.