Corrected entry: At the hospital, Michael must defend his father, so he and Enzo the baker stand on the steps to the entrance of the hospital. The Turk's hit men drive up, see them, and drive away. Very soon, McCloskey and a large group of cops drive up, sirens blaring. They obviously have been informed by the hit men of the Godfather's new protection, and are there to rectify the situation. The problem is, that from the moment the hit men leave and the police sirens are first heard, only 22 seconds have passed. There is no way in this cell phoneless era that the hit men could have found McCloskey, informed him of the changed situation, and then have this police task force assemble and drive to the hospital.
Greg Dwyer
8th Sep 2016
Correction: The police were likely right behind them to protect them in case something happened. When they saw that the car didn't stop and have its occupants exit, they drove up.
Greg Dwyer