Place it as the reaction beat right after the mistake lands in your edit. Pair it after the bomb has been planted announcement for doomed defuse attempts, or follow enemy spotted with it when your team still pushes in and loses the trade anyway.
このサウンドについて
This is a half-second voice clip of a Counter-Strike bot saying 'Oh boy' in a flat, resigned tone. It lands as dryly amused and slightly exasperated, like a teammate who already knows the round is about to go wrong. The line comes from the in-game bot chatter in Counter-Strike.