Emergency searchers scan for four things in two seconds: you handle THIS emergency, HERE, NOW, at a number they can tap. 'Burst Pipe? Franklin Plumber On Call. 20-Min Callback' beats any clever alternative. Speed and specificity are the entire persuasion.
Structure for it: emergency terms get their own campaign (their economics justify higher bids), ads say 24/7 only if it's true, the call button is the hero, and the schedule matches when a human actually answers. An unanswered 2am click is money donated to Google.
This is also where response-time infrastructure pays hardest: the caller dials down the ad list until someone answers. Being second-best at answering makes you a lead-generation service for competitors.