Crossword puzzle clue "when this sound stops you'll be left flat"

When this sound stops, you'll be left flat

Wrap right over left, tuck right underneath, pull, pinch right in a loop, wrap left around, push left through hole to create loop, pull loops

Hybrid car that runs a few seconds, then stops, then runs again, then stops again...?

Make the flat flat

Smash flat, as a flat

They may go flat outside a flat

Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start; etc.

Actor Penn who went to/left/returned to/left again Washington