Sloppy run in the beginning part but I manage to grab the trip there instead of later at the SOI cutscene. I mess up on the box launch after the cutscene and almost die from flood. I add a new box launch down the hallway. Finally manage to survive the final launch but then mess up on the final slide jump. Time can be almost around 3:25 or lower prolly.
Halo 3 Floodgate Easy in 3:33 by T3h Boar