The exact origin of this clip is not documented, so its life is really an online one. Short foreign language voice snippets like this circulate on soundboards because they are easy to reuse out of context, and Sie zu tun works the same way. The phrase stays partly mysterious for English speaking listeners, which helps it function as a generic reaction rather than a specific quote. It gets shared in short edits and group chats where a brief, serious sounding interruption is funnier than an explanation.