From Halopedia, the Halo wiki
During his retirement, Czernek was interviewed about his experience during the Battle of Mombasa at the Museum of Humanity. The shots shown during the interview broadcast are of Czernek viewing a commemorative diorama of the battle and of the diorama itself. At the beginning of the interview, Czernek is shown slowly approaching the diorama with a visible prosthetic in place for an amputated right leg. His leg is assumed to have been lost during the battle.
According to Czernek, during the battle for New Mombasa, Czernek and his unit began to run low on ammo while fighting the Covenant. He and his unit had to scavenge the ground for any available weapons and ammunition as they waited for support to arrive. Czernek continued fighting with an M41 LAAG on the back of an overturned Warthog when John-117 arrived with a primed grenade in his hand.
It should be noted that his testimony is not entirely reliable. While it is possible that Czernek fought in New Mombasa, the specifics of Spartan-117's intervention in the battle are fabricated, possibly by the ONI in order to cover up the true circumstances surrounding John's disappearance and the end of the war from general public as well as the existence of the Forerunners and the Flood.
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