Place it at the exact reveal in your edit, then follow it immediately with a shocked sound for the reaction shot, and finish with a bass boost discord call underneath the next line of dialogue.
このサウンドについて
This clip is a short earrape scream built around a loud shouted 'Ahhh! Two!' stretched across about four and a half seconds. The voice is heavily distorted and pushed to an extreme volume, making it feel jarring, chaotic and deliberately over the top rather than scary.