Possible Clues:

• Ticking peril
• It's up to me and mine and it's set to go off with a bang
• Thing set to explode
• Untrustworthy ticker made the enemy fail
• It'll go off after the designated period
• Nearly all this paper's a flop? It'll be a blast in due course
• Sentence builder carrying minute explosive device
• Ticking danger
• THE thing that will go off …
• Disaster just waiting to happen