Someone has already checked this. 401 eastbound near Keele St in the collectors. It is slightly uphill at this point but the slope is <1% and is not enough for a manual-transmission car to roll back in neutral - certainly not enough to roll back at the speed shown on the video. Check was done on the shoulder rather than in a traffic lane, but the slope is the same. The conclusion of the person who did this test is that there is NO possibility of that Acura having rolled back at the speed shown in the video, without it having been in reverse.
Other factors: Ragu has apparently owned that car for at least 4 years, so the argument of being unfamiliar with the car is hogwash. The manual transmission on that car has reverse at the bottom right (below 5th) not at the top left (next to 1st) so any potential argument about having accidentally selected reverse is also hogwash (and by the way, my car has reverse at the top left and you STILL can't get it in accidentally unless you have a habit of pushing down firmly on the shift lever with every shift).