Lone Wounded Marine
From Halopedia, the Halo wiki
Overview
An Easter egg found in the Halo 2 level Cairo Station. Play this level on the normal setting, it only works on this for an unknown reason. When you reach the loading hangar where you must defeat the first Covenant boarding party, ensure that you save the lives of all the Marines with you. When every last Covenant is dead look at your accompanying marines faces. One, in this room, will be cut, bruised and covered in blood. This is the only place in Halo 2 where such a damaged marine can be found.
