Gunfight Analysis--The Keith Prock Incident

This is another posting in a series where I explore just how fast a criminal attack can happen through analyzing actual video-recorded events. One of the critical challenges both police and private citizens face when confronted with a criminal attack is recognizing what is happening and then reacting fast enough to respond effectively. This is not trivial since the attack is often underway before a defender even realizes that there is a problem. Even if the defender has a planned response, the speed of the attack can often preclude them from effectively responding in time.

Maricopa Police Officers spotted Keith Tyler Prock at a Circle K gas station in Maricopa, Arizona. Since Prock had several warrants out for his arrest, officers at the gas station attempted to contact him. When he spotted the officers, he turned and ran with officers giving chase. As he was running, Prock drew a pistol and shot Maricopa Police Officer Sebastian Sanchez multiple (I believe two) times. The Sanchez survived and recovered.

Prock continued to fire at another officer who was also chasing him as well as two other officers who arrived during the gunfight. The other officers returned fire striking Prock who died at the scene.

So how fast did it happen? As mentioned above, Prock drew a 9mm pistol from his waistband as he was running. From the pursuing officer’s perspective, Prock’s motion in drawing the pistol looked exactly like someone pumping their arms as they ran. 

Prock Starting His Draw

So how much time did it take for Prock to draw and fire his pistol? His draw from the time he initiated the movement to the moment he fired at Sanchez was 1.535 seconds.

The Moment Sanchez Could Have First Seen Prock's Pistol

From the moment that Sanchez could have initially seen Prock's pistol (circle in the picture above) until Prock fired the first shot (see pictures below) was 0.567 seconds. Prock fired his second shot 0.560 seconds later.  

Prock Fires His First Shot at Sanchez

Prock Fires His Second Shot at Sanchez—The Brass 

Cartridge from the First Shot is Visible

The Force Science Institute conducted several experiments in a 2014 study to measure police officer reaction time to start and stop shooting. The experiment showed that a police officer who had already made the decision to act (i.e. pull a trigger) still took an average of 0.310 seconds to react to a visual stimulus.(1) 

If we subtract the experiment's 0.310 seconds from the 0.567 seconds Sanchez had to see and mentally recognize that he faced a deadly threat, Sanchez had only 0.257 seconds to decide. Even if Sanchez had his pistol in hand, finger off the trigger, with his pistol aimed at Prock it would have been a challenge to react in time. 

In this incident however, Sanchez was sprinting at full speed and he did not have is pistol in his hand. If we pair down COL Boyd’s Observe, Orient, Decide, Act cycle, to two elements: Observe, Act (act in this instance defined as drawing his pistol) it was not humanly possible for Sanchez to react to Prock’s deadly threat in time to prevent the assault. (2)

Also of note: If we assume Officer Sanchez could have reacted in time to prevent Prock’s assault, his shots would have likely struck Prock in the back. The value of body camera videos is apparent in this context since numerous police officers have been charged for shooting suspects in the back. Just because a suspect’s back is turned, it does not mean he is incapable of posing a deadly threat.

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(1)  During the Force Science Institute experiments to measure police officer reaction time to start and stop shooting, in one experiment the officers were positioned in a firing stance with a training pistol and were instructed to fire the pistol when a green light came on for 0.500 seconds. On average, it took officers 0.250 sec to begin the trigger pull (i.e. react to the stimulus) and .06 seconds to complete the trigger pull (defined as the actual travel time of the trigger from a position of rest to a position back against the frame) for a total reaction time of 0.310 seconds.

 

See: Lewinski, Hudson, & Dysterheft (2014). Police Officer Reaction Time to Start and Stop Shooting: The Influence of Decision-Making and Pattern Recognition. Law Enforcement Executive Forum 14(2), 1-16   

 

(2) If you are not familiar with COL Boyd’s Observe, Orient, Decide, Act cycle, it is worth reviewing. In a previous article (see here), I discussed the OODA framework and how it applies to armed encounters. For separate in-depth discussion of Boyd’s OODA framework go here.