In all the teaching I ever did, it was “if necessary, and the Officer life is in danger... ‘shoot to kill’ in this type of robbery and physical attack trying to take his gun. The guy is already a robber, and if he gets the gun, most likely he will shoot the Officer.
You are right, a few seconds at best... to make a life or death decision.
563.074. 1. Notwithstanding the provisions of section
563.016, a person who uses force as described in sections
563.031, 563.041, 563.046, 563.051, 563.056, and 563.061 is justified in using such force and such fact shall be an absolute defense to criminal prosecution or civil liability.
2. The court shall award attorney's fees, court costs, and all reasonable expenses incurred by the defendant in defense of any civil action brought by a plaintiff if the court finds that the defendant has an absolute defense as provided in subsection 1 of this section.
The 563.046 I bolded above is this one:
Law enforcement officer's use of force in making an arrest.
563.046. 1. A law enforcement officer need not retreat or desist from efforts to effect the arrest, or from efforts to prevent the escape from custody, of a person he reasonably believes to have committed an offense because of resistance or threatened resistance of the arrestee. In addition to the use of physical force authorized under other sections of this chapter, he is, subject to the provisions of subsections 2 and 3, justified in the use of such physical force as he reasonably believes is immediately necessary to effect the arrest or to prevent the escape from custody.
2. The use of any physical force in making an arrest is not justified under this section unless the arrest is lawful or the law enforcement officer reasonably believes the arrest is lawful.
3. A law enforcement officer in effecting an arrest or in preventing an escape from custody is justified in using deadly force only
(1) When such is authorized under other sections of this chapter; or
(2) When he reasonably believes that such use of deadly force is immediately necessary to effect the arrest and also reasonably believes that the person to be arrested
(a) Has committed or attempted to commit a felony; or
(b) Is attempting to escape by use of a deadly weapon; or
(c) May otherwise endanger life or inflict serious physical injury unless arrested without delay.
4. The defendant shall have the burden of injecting the issue of justification under this section.