As a professional equestrian, I feel I have the knowledge to suggest you take the time to train and desensitize your horse. If all it takes is for someone to scream to cause your horse to spook bad enough to kick or strike out, you've got a very green and/or traumatized horse. If you were flailing around in panic, this would be more rasonable, but just screaming shouldn't spook your horse to act out so dramatically. I would expect a jump off to the side, maybe even bolt if he or she is young, but to kick out at you proves that you need to work with your horse a little and develop it's confidence considerably. How do you expect your horse to tolerate the everyday occurances if he/she panics simply by any loud noise? If you ever plan to show, trail ride, ride off your property, or let anyone else (besides an accredited trainer) ride this individual, please desensitize and train your horse for the safety of your horse, yourself, and anyone else around.

Oof. Getting kicked by a horse is not a good thing. I would know. I got kicked by a really pissed off horse before, and trust me it wasn't a great experience.