Trump is ordering the military to kill people in Portland who resist fascism. Those are unlawful orders and every soldier has a legal obligation to refuse them. They swear an oath to the constitution not the president.
Soldiers have a duty to disobey orders that are unlawful. It is not insubordination to do so, it is a constitutionally mandated act and an act of courage. Troops must not harm civilians, doing so is illegal and they know it. Remember the My Lai Massacre and the Nuremberg Trials.