From the Officer Down Memorial Page:
Corporal Mark Coates was shot and killed after stopping a car for weaving in traffic on I-95 near the Georgia border.
During the traffic stop the subject began to struggle with Corporal Coates and they both fell to the ground. The man fired a .22 caliber handgun into Corporal Coates' chest, but the round was stopped by his vest.
Corporal Coates was able to force the man off of him and return fire, striking the him five times in the chest with his .357 caliber revolver. As he retreated for cover and to radio for backup, the man fired another shot. The round struck Trooper Coates in the left armpit and traveled into his heart.
The man survived the incident and was sentenced to life in prison.
Corporal Coates was a U.S. Marine Corps veteran and had served with the South Carolina Highway patrol for five years. He was survived by his wife, two sons, two step-daughters, parents, sister and brother.
Read more: http://www.odmp.org/officer/420-trooper-mark-hunter-coates#ixzz3xkypdEPC
The tragic lesson to be learned here is "non-purposeful tactical errors." After Corporal Coates got to his feet, he backed away from the subject, but did not utilize cover and was shot in the armpit as he used his radio. 1) shoot until the threat is eliminated, 2) seek time, distance, and cover.