The idiom to dodge a bullet means to have managed to avoid injury disaster or a negative situation. To 'dodge' means to move so that you escape something. To dodge a bullet means to avoid a situation that could be potentially harmful or dangerous.

1. At first I was so disappointed to miss out on that job, but when I heard that the company went out of business a week later I realized I'd dodged a bullet!
2. Looking back, I think I managed to dodge a bullet by dropping out of medical school. The hours junior doctors are expected to work these days are crazy!

1. I broke up with Karl because he was behaving in a controlling way. I think I dodged a bullet there.
2. The house I was interested in buying has decreased in value by over 10,000 Euro I really dodged a bullet.