Since he was a race horse, pulling on him wouldn't have done any good anyway, am I correct? They use something like the pulley rein to slow them down I think, right? This is not your normal runaway horse, though, but one that is trained to run a certain way, so again, a different thing than highlighted in the OP's original post
I mainly stated what I said since you said you would never turn a horse at high speed; trust me, I have seen alot of barrel horses who have not been taught how to turn properly, and they are still able to turn without slipping and falling...so there is still risk even there.
I still think it comes down to that "life or death" instance, and what you can actually get the horse to do, in order to get him TO slow down or stop.
As I've mentioned, I have slowed horses by slowly turning them into a circle, and then being able to utilize the ORS effectively on a runaway horse. BUT I also know how to ensure that the horse remains balanced as well. I've never had to use the pulley rein to get a horse to slow down or stop, but I do know how to implement it if I have to. I'm not trying to argue over this, either, so please don't take it that way.