Related Clues:

• "Safe!" or "Out!"
• Umpire's ruling
• ___ and response ('human microphone' technique at Occupy Wall Street)
• Word with "role" or "house"
• One might set a precedent
• Thing often dropped in a tunnel
• Be an umpire
• Multiple-___ (like some exams)
• One may be close
• Telephone made from aluminium coated in chlorine
• See 17
• See 25
• See 14
• See 21
• See 11