Place it right after the reveal that causes the panic, as the immediate reaction beat. Lead in with dun dun dun for the shock, follow with this clip, then close the sequence with the SpongeBob Fail sound for a deflated ending.
About this sound
A short vocal clip of someone whimpering the words oh god in a shaky, strained voice that lasts just over three seconds. It sounds tearful and overwhelmed rather than loud, which gives it an awkward, funny desperation that lands like a tiny meltdown caught mid-panic.