I think it's relevant to assess what Rittenhouse's intentions, or lack thereof, really were. If he was being realistic about his stated role at that protest, he would understand that killing a person in a crowd like that, deserved or not, will always draw people trying to disarm him, and surrendering his weapon after shooting the first person would reflect that. The fact that he continued to shoot more people is very clear evidence that he saw all protesters as the enemy and shot indiscriminately. Even if the first shots were self defense, he is not an operative of the law, and cannot just continue shooting at anyone trying to apprehend him after shooting someone in a crowd.