Possible Clues:

• Tear up poster very quickly
• Quick pasta sauce keeps the runs in
• Direction in 23-Across
• What's left in the river after the hay, by the sound of it
• Hey ..., according to the magician
• Word said with a wave of the hand
• What's left in the river may go with the hay, by the sound of it
• Hey, quickly for a magician
• This may be played very fast after 27 across for the magician
• Fast, in music