Babylon 5 is science fiction. But, this is a depiction of soldiers shooting at each other over illegal orders.

[TexLaProgressive]

1. We of a certain age do not need fiction My Lai, Vietnam

While Thompson did not have to fire on US soldiers I am possitive he would’ve if they did not stop the slaughter.
https://armyhistory.org/my-lai/

While the massacre was occurring, an observation helicopter piloted by Warrant Officer (later Lieutenant) Hugh C. Thompson was flying around the My Lai area at treetop level. Thompson was part of an aero scout unit from the Americal Division’s 123d Aviation Battalion and his mission was to locate enemy forces and relay this information to friendly ground forces. Thompson and his crew saw that a lot of people had been killed; there were as many as 150 dead in a ditch near the sub-hamlet. Thompson also could see that a large part of My Lai was on fire and was being systematically destroyed.

Upset about what he and his crew were seeing, Thompson landed his helicopter between fleeing Vietnamese and pursuing U.S. soldiers. He then ordered his door gunner, Specialist Four Larry Colburn, to fire on the Americans if they refused his direction to break off the chase. After a tense confrontation with the officer leading the soldiers, later identified as Second Lieutenant Stephen Brooks, the Americans ceased their pursuit. Shortly thereafter, Thompson and his crew also were able to evacuate a few living Vietnamese civilians, very likely saving them from serious bodily harm, if not death.