Coincidence driving key plot points is usually considered poor writing. However, I like that we get to find out what happens to some people because they show-up again in a later episode.

For example, the basketball player that Bobby saves who buried in the parking garage after the earthquake returns to save him at the end of S6 when the freeway collapses.

You'd be more likely to win the lottery. Yet, the 118 regularly runs into people from the past. It's weirdly satisfying to find out what happens to some of the rescues afterwards.