Something to note here based on some comments - if Ryuzaki Kagura did indeed attempt to kill the mayor using a gun, then that means that Ryuzaki Kagura is carrying a gun unless he had previously dropped it.
Attempting to kill the mayor over taxes is an act of terrorism by definition.
If a suspected terrorist is fleeing with a gun, which is either concealed on in their hands, Police ARE allowed to use lethal force if the suspect is at risk of escaping.
When the suspect entered that car, and the driver assisted him, the driver became a terrorist, more or less.
The SWAT officer was seemingly alone in that chase, and the sports car presented an imminent threat of escape - lethal force was justified at that point.
Now, the SWAT officer seemed to believe that Ryuzaki Kagura was a terrorist, if he was not, then the officer was mistaken, but is still allowed to do what he did as he believed otherwise. For the wrongly-accused suspect to avoid dying wrongfully, he had the option of cooperating.
No comment as of yet about Bankai not RPing within the confines of the rules.