Possible Clues:

• Firm assigns worker to a barricade
• Determined and unyielding
• Firm employs a worker to fix blockage
• Data man can be quite unyielding
• One person in 6 changed, becoming intransigent
• Determined and unyielding to requests
• The first male worker is uncompromising
• Notice a bloke over time becoming unshakeable
• Firm's first man takes on worker
• Resolute, refusing to yield