If this is a matter of “every second counts” then wouldn’t it be more valuable for them to be sitting in their idling cars drinking their coffee rather than Starbucks?
I have started a car an estimated 5,000 times in my life, and that’s a conservative estimate. (Nine years of driving minus two years of not owning a car, assuming two starts per day = 7×365 x 2 = 5,1110), so I’m going to consider myself reasonably well-versed in the process of car starting. It involves the following steps: (1) locate keys, (2) insert into ignition, (3) turn key, (4) put car in gear.
Since these are police cars with presumably no risk of being stolen, you could even leave the keys in the ignition, eliminating the process of finding keys or putting them in the ignition. Further, whether the car is left idling or not, you still need to put it in gear. So leaving the car idling only eliminates the physical turning of they key, which I would estimate takes me approximately half a second. Let’s be generous though, and call it a full second.
Now, let’s say the distance from the closest seat to the door in Starbucks to the door of the police car is… 50 meters? That would take Usain Bolt, the fastest man on earth, 4.79 seconds, assuming the same pace as his world record 100m time of 9.58 seconds. And let’s not forget opening the Starbucks door (maybe 1.5 seconds?) and opening the car (another 1.5 seconds?)
So all said and done, if these police officers were the fastest men on earth AND they had access to the seats nearest the door, sitting in the Starbucks is still tacking on 7.79 seconds, which is more than SEVEN TIMES longer than the process of turning the key that is already in the ignition. I don’t think the “every second counts” argument holds much water, here.