First of all it's easy to sit and armchair a situation like that and in hindsight to boot. We weren't there. We shouldn't assume what the federal officer was feeling. Second, same officer _had_ been injured and had his foot in stitches from another "protestor" who had driven into him not long ago.

Driving into someone is what's considered lethal force in law enforcement. The woman got shot after consistently ignoring police commands and then enacted lethal force on a federal officer. There's no ambiguity here.