Darnell running in Dealey Plaza on a different day. Generally looks the same.
I believe we need to keep the time frame of the above images in mind when naming the suited man running across the Knoll as Darnell. Darnell took a while to cross Elm St to its' (N) side. He then at some point traveled well behind the Pergola to film the railroad cars area and the Throng of people that were Already situated back there, and traveling back and forth up/down The Steps. Plus, there was already a heavy contingent of law enforcement back behind the Pergola at this point in time. When you consider some of these enforcement officers were initially examining the man hole cover on the South side of Elm and then Eventually went across Elm and Then focused their attention on the railroad car area behind the Pergola = a serious amount of time passing for Darnell to possibly film all of this and then be sprinting across the Knoll. Sitzman is a good person to use as a rough time stamp for this footage. Sitzman is also photographed in front of the TSBD shortly after the assassination. If that is Darnell running across the Knoll in the footage above, then I believe the photos of Sitzman in front of the TSBD would have to be somewhere in the neighborhood of 1 hour or more after the assassination. I do not believe those photos of Sitzman are close to that long after the assassination. Therefore, I do Not believe we are seeing Darnell in the footage above running across the Knoll. The cavalierly accepted time stamping of film and still images of the JFK Assassination continues to hinder this investigation.