If there are cities on Mars in the second half of this century with say a million people, they will be living in engineered structures and sustained by agriculture in protected, controlled environments.
If there was an asteroid impact on Mars with the mass and velocity that would classify it as an Extinction Level Event if it had hit Earth, would they also become extinct?
While Mars is slightly smaller than Earth, it's a lot closer to the asteroid belt, so these kinds of events are just as relevant to "them" as they are to "us". Even more so perhaps.
Assume the impact is not necessarily a direct hit on the city itself, or that they are widely spaced enough that at least some are far from the impact.