From the last cutscene in the Halo 2 E3 2003 realtime demonstration. The Master Chief escapes in a Ghost from two pursuing Phantoms.
In the final scene of the Halo 2 E3 2003 realtime demo, the Master Chief is confronted with several sword Elites. Cortana taunts him, saying "bet you can't stick it", to which the MC responds, "you're on", and the film fades out on that scene.
From the Halo 2 announcement trailer. The Master Chief skydives out of Fighter Bay 02 aboard The Spoke, aiming himself towards a passing Covenant cruiser.
Chinese characters on the side of the Chief's new assault rifle read out "monkey king". It's a reference to a famous Chinese myth that is also mentioned (incidentally) in the audio commentary for "Crouching Tiger, Hidden Dragon".
A shot from the announcement trailer showing the elevator shaft that carries the MC to Fighter Bay 02.
Looking over the MC's shoulders, through the window of Fighter Bay 02 to see the "glassing" of Earth by Covenant energy weapons. From the announcement trailer.
From the announcement trailer. The Master Chief opens a weapons rack that is concealed in the hallway wall and selects an assault rifle.