So unless I misinterpreted the way it was related, that's exactly what happened. The car was going SB, wanting to U-turn and go back north and the nice folks going NB, all three lanes, knowing they really had no where to go, all stopped and opened a corridor across all three lanes, open to the turn only lane. Now, given all sedans, the rider might have seen the car coming through that corridor on an intersect course. But with the preponderance of SUVs and trucks, the riders only clue would have been a one car gap between the Good Sam in the lane nearest him. Then SHAZAM, a car appears through what appeared to just be a randon gap in the nearest lane.
So, yes, it's entirely possible that the rider was not going faster than 25mph. Probability? Cant say, but at least 50/50.
And this is the downfall of the Good Sam sort of driver. Like the "Giver" that yields thier ROW to you, throwing traffic into chaos beucase everyone around no has no idea whats supposed to happen, if you cant see the variables, DONT mess with them.