The biggest mistake the agents made was escalating a traffic violation into a dangerous situation that ended in the killing a woman with 3 kids, a US citizens a with a criminal record that consisted of one traffic ticket.
Instead of calling a tow truck to move the vehicle, the agents decided to treat her as a dangerous felon. So these masked men with no badges boxed her vehicle in, pointed loaded guns at her, screaming at her to get out of the vehicle and attempting to enter the vehicle. She did what most lone women would do in this situation, try to escape.
If this is an example of how ICE treats US Citizens, I would hate to see how they treat detainees.