Place it right after the confusing moment in your edit, then follow it with No No Wait Wait when the explanation starts to unravel, and use Oh My God Wow for the reveal that finally answers it.
关于此声音
This is a short spoken German phrase asking what is going on, lasting just under six seconds. A single voice delivers the question with a puzzled, slightly confrontational tone, as if catching something odd in progress. It feels funny and awkward at once, turning confusion into a direct challenge that asks for an explanation right now.