Place this warning just before the visual payoff in your edit, then follow the fallout with a no no wait wait reaction for extra panic, and close the sequence with a sudden suspense hit if the outcome needs one last beat of consequence.
Über diesen Sound
A short voice clip of just over two seconds with a person urgently shouting stop, don't do it in a panicked warning. It feels tense and funny at once, because the alarm in the delivery turns an ordinary bad idea into an emergency worth stopping immediately before it goes wrong.