Dodge a/the bullet
Definition 1 of 1
Pro Tip 1/3Narrow Escape
Emphasizes narrowly avoiding something potentially harmful. 
She dodged a bullet when her faulty car brakes didn't cause an accident.
Pro Tip 2/3Colloquial Usage
Used in informal speech, not in formal writing or formal speeches. 
When his ex started causing trouble at the party, Mike dodged a bullet by leaving early.
Pro Tip 3/3Not Literal
It's a metaphorical expression; there's no actual bullet or dodging. 
Finding that error in my report before it was sent out meant I dodged a bullet!