what about the nonsense on the quantum system? i think the reporter left some key info out. why does speed is a factor to mitm attacks? the slide shows a prope

what about the nonsense on the quantum system? i think the reporter left some key info out. why does speed is a factor to mitm attacks? the slide shows a proper mintm diagram... or is this quatum thing exploiting a package arriving before the honest response? and why they would need to do that if they are in a position to do a proper mitm attack and not expose themselves for someone who monitors man-on-the-side attacks?