I suspect that the officers did at least make some effort to rescue the car thieves, however, I figure these girls are entirely responsible for their own deaths in this case - thus if the officers determined it was not safe to rescue them, then that's just the way the cookie crumbles. No sympathies from me here I'm afraid.
Expanded - Ya know, up here, if someone drives their truck on an ice road before the "all clear" is given, and their car breaks through, it is absolutely not expected of the police to dive in and rescue them. I do not see why this case is any different...