Possible Clues:

• One who's bound, initially, to put on an act
• Key defender, one bound to provide entertainment
• Houdini, for example
• Performer who's bound to start act, but not to finish it
• Police tag's so unreliable for one managing to break free
• Game played when up against difficult case, meaning one may be tied up at work?
• Might one have got tied up at work?
• Someone who gets tied up at work?
• Key defender, star who's bound to draw crowds?
• Term that 20 Across coined for himself