Possible Clues:

• One directly responsible for health cuts?
• One opening in the theatre
• Theatrical knife?
• Places left in a mess by surgical instrument
• To cut skin off head and half of heel, use this?
• Used to 6 down various places listed to open
• Sharp blade
• Surgical knife with a short thin blade
• Notes admit pressure put on novice? It's only called for in some theatres!
• It cuts line in various places