He displayed conspicuous gallantry and intrepidity. While helping clear enemy mines from a road, he stepped on a well-concealed S-type antipersonnel mine. Hearing the characteristic noise indicating that the mine had been activated and, if he stepped aside, would be thrown upward to explode above the ground and spray the area with fragments, surely killing two comrades directly behind him and endangering other members of his squad, he deliberately placed his other foot on the mine even though his best chance for survival was to fall prone. Pvt. Wallace was killed when the charge detonated, but his supreme heroism at the cost of his life confined the blast to the ground and his own body and saved his fellow soldiers from death or injury.