( I do know that retail security guards are regularly trained not to peruse thieves into parking lots precisely because of dangers created once vehicles are involved. )
If they are not trained in how to approach and deal with suspected wrongdoers driving cars, something that is not uncommon in large facilities, that lack of training is a serious issue for their employers.
Still, my heart goes to those hurt and I wish them quick recovery and no permanent damage.
I think the uncontested parts of the story say that the driver is in big trouble here for using lethal force against them, but I also think the guards should be trained not to put themselves in harm's way.
One detail is that Tesla alleges that they 'accelerated' in reverse. This is completely abnormal and if it can be corroborated by the physical evidence, it will be very troublesome for the driver.
Further, I have to believe that Tesla has no shortage of people who know about accident reconstruction and who can determine the idle speed & mass of the jeep and compare that with the force needed to cause skid marks or to have knocked the employee whatever distance. If they were to do that, it would be very interesting because we all know just how skilled their engineers are, from Elon on down.