Reaching the High Charity conduit
From Halopedia, the Halo wiki
To do this, simply play through the level until you reach the part called "Once More, With Feeling" and turn to either your left or right. You should notice a crate. Jump onto it and then crouch jump onto the conduit. From here you can walk to the glowing start of the conduit, or complete the level without fighting at all by walking the other way. This could be considered an easier way to achieve a speed run, although a generally unacceptable one.