Did You Major in Marine Bio? Achievement in Halo: The Master Chief Collection

This achievement can be earned on the Easy difficulty (or higher).

At the very end of this mission, after the Falcon ride to the beach with the anti-air turrets, you are going to have to turn around and trek back the way you came...on foot. It's worth noting that you will need a Jetpack in order to complete this journey, as some rock traversal is necessary. Keeping that in mind, refer to the video guide below, courtesy of Halo Completionist, for further details explaining the path to take; a text-based solution would be much too difficult to follow.