Landing Helicopter Between Soldiers and Civilians: Thompson landed his helicopter between advancing Charlie Company soldiers and a group of Vietnamese civilians hiding in a bunker. He confronted the ground troops and ordered his crew to fire on the Americans if they tried to harm the civilians. This act of placing himself between his own countrymen and their intended victims was virtually unprecedented in military history.

Ordering Crew to Fire on American Soldiers: Thompson gave his door gunner Lawrence Colburn explicit orders to open fire on American soldiers if they attempted to harm the Vietnamese civilians he was trying to protect. This order to fire on fellow Americans to prevent a war crime was perhaps the most dramatic individual act of moral courage during the Vietnam War.

Reporting the Massacre Through Chain of Command: Thompson immediately reported the massacre through his chain of command, including to Major Fred Watke and other officers. His reports were suppressed, ignored, or dismissed as combat stress. The military hierarchy's refusal to investigate Thompson's urgent reports enabled the cover-up to persist for over 18 months.

Vilification and Death Threats: Rather than being honored for his courage, Thompson was vilified after the massacre became public. Congressman Mendel Rivers tried to have him court-martialed. Thompson received death threats, threatening phone calls, and dead animals left on his doorstep. Fellow soldiers ostracized him as a traitor to his unit.

Thirty-Year Delay in Recognition: Thompson was not recognized for his heroism until March 6, 1998, when the Army awarded him the Soldier's Medal, thirty years after My Lai. The ceremony also honored crew members Lawrence Colburn and posthumously Glenn Andreotta. The three-decade delay reflected the military's prolonged resistance to acknowledging the massacre and honoring those who tried to stop it.

Return Visits to My Lai: Thompson returned to My Lai several times after the war, meeting with survivors of the massacre. During a 1998 visit, he met the man rescued as a child from the ditch by Glenn Andreotta. These visits became powerful symbols of reconciliation and personal accountability.

Military Ethics Education Advocacy: After receiving belated recognition, Thompson became one of the most influential advocates for military ethics education in America. He spoke at military academies, training facilities, and schools about the duty to disobey unlawful orders and the moral responsibility of individual soldiers in preventing war crimes.

Confrontation with William Calley: During the massacre, Thompson directly confronted soldiers and relayed to his superiors that American troops were killing civilians. He specifically saw Lieutenant Calley's troops herding civilians into the ditch. Thompson's real-time reporting and intervention provided some of the most powerful evidence of the massacre's deliberate nature.