Perhaps one of the biggest mistakes we can make is getting caught up in the immediacy of the moment, becoming so fixated on a mission at hand that things become blurred at the periphery. Unfortunately, innocent bystanders are often found on the periphery.
We have the collateral responsibility to correctly assess appropriate responses to deadly force threats, remaining conscious of fields of fire and the presence of innocents who may move in and out of the kill zone. This includes the possibility of hitting fellow officers due to crossfire alignments, or not recognizing off-duty or plainclothes officers who are actively engaging suspects. Taking advantage of appropriate cover and concealment can mitigate friendly fire threats, as can alerting officers of one another's presence and granting them the split second it may take for mutual recognition.
Overestimating one's ability to handle a patrol car can lead to a fatal accident. We often perform in an exemplary manner under controlled conditions. But once placed in an uncontrolled arena—replete with sharp corners and oiled pavements, inclement weather, and unpredictable motorists—our skills may prove lacking. While the most common patrol car accidents involve backing maneuvers, most officer-involved fatalities stem from emergent call responses and pursuit driving.
When faced with an individual who's acting strangely, we can also err in not recognizing a dire medical emergency, attributing the person's behavior to some ingested substance instead of a possible diabetic reaction or seizure. This type of miscalculation can result in actions that aggravate the problem instead of resolve it. At such times, remembering the Hippocratic Oath of "First do no harm" is a very good idea.
Arbitrarily ignoring problems or kissing off reports can leave citizens vulnerable to escalating threats. Nowhere is this more pronounced than in matters of domestic discord.