User blog comment:SPARTAN 119/Apache (Viet Cong sniper) vs Ann Matsura (Busou Chuugakusei: Basket Army)/@comment-1061145-20130307030007

''At that moment, however, he could have sworn he heard sensed someone behind him. Practically the second after this occurred to him, he felt a rag soaked with some sort of chemical pressed against his face. Youji passed out instantly. ''

Chloroform rag. Works like a charm.