How many different topics are being discussed in this thread?
I'm still unclear if the officers just "happened" to be following the would-be victims, or if the would-be victims were being followed by police. Were these people under surveillance or something?
Shooting out the tires does not stop a car unless it going very fast. A car could actually could continually ram another car without any tires at all. So that would be foolish of the cops to do. However, perhaps getting out of the way was an option. You know, step aside, get a license#, and send out an APB to pick up a bunch of drunk guys in a car that looks like it just hit something at 4am.
The only way I could see this justified is if these were dangerous criminals - since I am unaware of any arrest warrants or anything, that does not appear to be the case.