Put this clip immediately after the peek in your edit, then layer a Sudden Suspense hit before the reveal and follow with a Huh reaction when the person notices the camera and freezes in the doorway.
About this sound
This clip is a short spoken line lasting just under four seconds, a man asking in disbelief, 'Who looks round the corner like that?' The delivery sounds baffled and amused, turning a simple peek around a corner into something suspicious. It comes from a Caspersight clip where the question is aimed at an odd way of looking around a corner.