Breaking Quarantine
From Halopedia, the Halo wiki
Breaking Quarantine is a story in the Halo Graphic Novel, depicting Sergeant Johnson's escape from the Flood. Illustrated by Tsutomo Nihei.
Summary
Following contact with the Flood, Sergeant Johnson managed to avoid being overwhelmed by Infection Forms. He fired at an Infection form which had latched onto a fellow Marine (presumably Private Mendoza), killing the Flood. He watched as the Marine transformed before his eyes into a monstrous form (what we know as Combat Forms). He took a blow to his arm from the Flood's tentacles and was thrown out of the containment room, across a large observation chamber and into the wall.
Several infected Marines started to approach him and he made a run for it, but ran into a sealed door. He tried to hack it, but the doors remained shut. An infected Marine fired a shotgun shell that richoeted off a wall, missing the sergeant. The sergeant dove below, unloading the last remaining rounds in his Assault Rifle onto the infected soldier. He grabbed his Pistol and made his way across the broken Energy Bridge, throwing a Grenade behind him, killing his pursueres. He stepped onto the lift, glad to finally escape the Flood. How he later managed to survive the destruction of Halo is explained in Halo: First Strike.
