Possible Clues:

• It is quickly inside more than half the joint?
• Doctor tries new sort of lock
• & 15 Across 10 is in Death In Venice and 10 (now showing)
• Recess for a secretary
• Type of lock; moister (anag.)
• The hollowed-out part of a traditional wooden joint, into which the tenon goes
• Tenon recipient
• Hole in wood for a tenon; sit more (anag.)
• Perhaps one might get ten on in it