I'm in pure musing mode here. When I'm driving down the highway when traffic isn't an issue and I don't have cruise control on, I often find myself gradually slowing down. My spouse responds to those conditions in the opposite direction, lol. I wonder if some of the rushing/slowing phenomenon is linked to personality type.
I can see how looking at a full page or two of sixteenth notes in both hands would send the speed message. That you were already in a heightened adrenaline state would only add to that.