Related Clues:

• Running exercise class on oxygen
• Carrying on business - with a knife?
• Running ordinary exercise class
• Controlling Aida, perhaps, with the sound of a bell
• What surgeon might be doing -- lecturing about physical exercise
• What's surgeon doing lecturing about exercises?
• Oscar training, sailor running
• Controlling machinery
• Spouting off about exercises working
• Opportunity strikebreaker provided for knight working in theatre
• Choosing to save time working
• Ordinary exercises sailor's managing
• Word with room or system
• Go over, stifling unusual painter working
• The 'O' of iOS