As far as I understand it the APD did nothing wrong, the redzone is what is inside of the walls of the hideout, and cops only need to respond to a situation in waves if it is a redzone. Since they were not going into the redzone they shouldn't have needed to respond in waves. Plus I have seen numerous higher ups do the same exact thing.
Just leave it how it is, let the cops use there own common sense, if they think they can get the person safely out of combat then let them, but if they attempt to do that and the person being escorted is killed its there own fault. In my opinion nothing needs to be changed, making it so people are invincible while escorted will become a problem with people abusing it.
Lets keep in mind that you are not in America when you play Altis Life. It is a completely different area. And from the looks of it its a police state, with that being said If there was a country like this in real life, the police would probably be doing much worst things then "shooting through a door".