I agree with everything you wrote, but one comment on that last phrase in your post.
They weren't authorized to use deadly force against someone with secret service protection. He wasn't even there for starters. They were authorized to use deadly force if there was a danger of death of serious physical injury.
Here is what it says verbatim:
1. Law enforcement officers of the Department of Justice may use deadly force only when necessary, that is, when the officer has a reasonable belief that the subject of such force poses an imminent danger of death or serious physical injury to the officer or to another person.
A. Deadly force may not be used solely to prevent the escape of a fleeing suspect.
B. Firearms may not be fired solely to disable moving vehicles. Specifically, firearms may not be discharged at a moving vehicle unless:
i. a person in the vehicle is threatening the officer or another person with deadly force by means other than the vehicle; or
ii. the vehicle is operated in a manner that threatens to cause death or serious physical injury to the officer or others, and no other objectively reasonable means of defense appear to exist, which includes moving out of the path of the vehicle.
C. If feasible and if to do so would not increase the danger to the officer or others, a verbal warning to submit to the authority of officer shall be given prior to the use of deadly force.
D. Warning shots are not permitted outside of the prison context.
E. Officers will be trained in alternative methods and tactics for handling resisting subjects, which must be used when the use of deadly force is not authorized by this policy.
F. Deadly force should not be used against persons whose actions are a threat solely to themselves or property unless an individual poses an imminent danger of death or serious physical injury to the officer or others in close proximity.
2. Officers should seek to gain voluntary compliance before using force if feasible and if doing so would not increase the danger to the officer or others.
3. Officers must prevent or stop, as appropriate, another officer from engaging in excessive or unlawful force, or force that violates DOJ policy.
4. Officers must request and/or render medical aid as appropriate.
I'm Gipper