My horse does the same thing. I almost flew out of the saddle when he does them wicked fast turns. He plants his butt and turns faster then my thinking them reacting so i have to react first them think. LOL. I say the trucked did right. He wasn't for sure if you were going to run in front of him. and let me tell you. You wouldn't nor your horse be alive if he did hit you. (You probably figured that out though but....)
Trouble rides a fast horse.....(Shrug)..... I ride a faster one.
I'm your HuckleBerry- Doc Holliday, Tombstone.