Lets remember the situation. The Capitol complex is being stormed by a pro-Trump insurrectionary mob set on overturning the results of the election through violence. At this point Capitol Police have lost control of the mob and are in the process of evacuating members of Congress to a secure location. The doors being smashed down are the entrance to the Speakers Lobby. On that afternoon that was the last barrier before the insurrectionists got into immediately physical proximity to members of Congress. That was the last line of defense. Its just a few more yards once youre past that door.
This is not only the lives of numerous Representatives, Senators and staffers. Its also multiple members of the succession to the Presidency: the Vice President, the Speaker of the House, etc. So its numerous individual lives and the continuity of government itself.
The video footage weve all seen shows one officer inside the entrance way guarding the door. With his pistol visibly drawn and aimed at the insurrectionists beating on the door he repeatedly warns the mob banging on the door to come no further. At this point Babbitt breaks through the upper window panel on the door and is shot. The single shot proved fatal.
The foundational justification for the Capitol Police to have firearms is to protect Congress individual lives and institution and the orderly functioning of the United States government. This standoff clearly and immediately implicated both those core missions. Babbitt ignored repeated warnings and the visible threat of lethal force.
https://talkingpointsmemo.com/edblog/important-info#more-1380105