Halo CE: Began on Pillar of Autumn in space. Ended in Longsword flying away from ring.
Halo 2: Began in space on Orbital Mac Cannon platform orbiting earth. Ended on forerunner ship headed towards earth.
Halo 3: Began on forerunner ship near earth (Cutscene). Ended on Foreward unto done split in half as chief enters cryo.
Halo 4: Will begin on Foreward unto Dawn. Will end…?
Every Master Chief Halo Game has began on a ship in space and ended on a ship in space. I would not be surprised if Halo 4 ended in the same way. Perhaps chief will destroy Requiem and escape from it at the last second into space?