Place it just before the moment of failure in a short edit, then follow it with the Fail Sound Meme to underline the collapse, and save the Darth Vader Nooo for a later, bigger denial so the two refusals do not compete.
關於此聲音
This short clip is GLaDOS, the cool-voiced artificial intelligence from Portal, repeating no again and again in a rising, panicked denial that lasts just over two and a half seconds. It feels funny and tense at once, like a machine losing control while trying to stay calm, and it works because her flat delivery makes the panic sound even more dramatic.