From Halopedia, the Halo wiki
Not to be confused with Release.
Released is the second track (Disc 1 Track 2) in Halo 3: Original Soundtrack, and plays during the Halo 3 campaign level Sierra 117. It is composed of Released (0:00-2:20), Wild Life (2:20-3:22), and Another Walk (3:22-5:20).
Released (2:20) starts with a single low note, followed by a section of percussion. A layer of high strings joins in with suspense, followed by some digital sound effects. The choir then enters, singing the main melody of Impend from Halo 2, albeit in a slower tempo. The soft drums and strings return as accompaniment. The vocals fade out, leaving the drums. The piece plays at the start of the level, as John-117, Avery Johnson and Thel 'Vadam are walking through the jungle, and continues throughout the first combat encounter.
Wild Life (1:02) begins with low strings building tension, before the drums once again become the dominant instrument. The slow drum beat gradually accelerates, soon replaced by a faster and louder tempo. It ends abruptly. The piece plays after the area where Reynolds is being interrogated by a Jiralhanae Captain, as John-117 and 'Vadam make their way towards the river.
Another Walk (1:58) transitions into a percussion part with a more relaxed beat, characterized by a more muted drum tone. The choir then joins in with the melody of A Walk in the Woods (alluded in the name of the piece), with the percussion beat playing throughout. It ends with a cymbal clash. The piece plays at the river encounter, after the Pelicans are shot down by Banshees.