The link that another FReeper sent does not have any reporting that the Blackhawk’s engines were for two hours running at “full bore”
RCJ mentions "running at full bore"... perhaps he said "throttle", not bore, upon another viewing of his vid.
Here is the short blurb with the advance notice: "EXERCISE: Monday morning, June 7, we will be working with our federal, state, and local partners on a routine training exercise on the grounds of the U.S. Capitol. Please do not be alarmed if you see emergency vehicles and low flying helicopters."
So, the picture is thus: 4 armed military blackhawks land facing the capitol, full bore/throttle, no apparent activity with troops or capitol police. IMHO, I think the capitol police were merely contributing a chopper for aerial filming.
U.S. Capitol Police twitter goes into their "version" of the events that morning
IMHO, and as a longtime FR I sincerely believe this, this so-called "exercise" was a message from the DOD to the Capitol, in reference to 11.3/11.4 of the DOD War Manual
For the other related RCJ's videos of this "exercise", you'll find them on his Telegram channel: