Let’s focus on the general conceit: There’s a bomb on this bus. If the bus goes below 50 miles per hour, the bomb will detonate. 

Yost throws in a new hurdle at every opportunity… an incapacitated driver, excessive freeway traffic, etc… BUT he always makes sure we’re aware the falling spedometer… 55, 54, 53…

Our hearts race as the number drops. It’s better than a ticking clock.