Place it early in an edit, just before the reveal, then follow it with Dun Dun Dun to heighten the wait, or open with Door Knocking Sound and let this clip carry the moment after it.
About this sound
This is an 11-second recording of faint, repeated knocks on a door, three short taps at a time with a low, muffled thud. It creates an uneasy, on-edge feeling, like someone is waiting nervously outside and unsure whether to knock again.