In DC, no way will a black officer get into legal trouble for shooting a white Trump supporter. If they bothered to charge him, no DC jury would convict.
I don't think it will matter if the officer or whatever is black or white. Not sure it's an officer. Photos seem to show the shooter wearing a white dress shirt with cufflink. Could be a congresscritter, or many other other types of people. Since the person was armed, it could be an officer, but is not certain.
She broke through a window and started to climb through. It is not unreasonable to think she was a threat. Not real easy to tell she was female, the way she was dressed, either, from what little I saw in the video.