Beat, beat, beat...
NEVER USE "BEAT" ANYWHERE IN YOUR SCREENPLAY! As has been said earlier, a beat is a DIRECTED action. It should be left up to the director and actors where the beats come in. If you want to imply a pause, fade in dialogue, or stop in action, use an ellipsis for fades (..., as was used at the beginning of this message), and use a double hyphen for an interruption (but--).