The literal text of their training and the perspectives of the people who train them and work with them have very little todo with each other. Furthermore, behavior like this is fairly consistent across departments.

There is also a well-documented history of police coming up with convenient excuses to do whatever the hell benefits them most (see also: bodycam "malfunctions"). Don't want to get involved in a dangerous situation? Whoops, I forgot my radio! Whoops, we don't have the right gear! Guess we can't get involved for more than an hour!