I use breakaway headcollars on a new horse at turnout only, when I don't know how easy they may be to catch again! The type I've got is made of a webbing material with velcro release points on the noseband and one side. It has clips so you can change it back to a normal headcollar for leading, etc.
I wouldn't want to lead a horse in a breakaway collar
. Since you were leading your horse into it's stall when the accident happened, I'm not sure how this item of equipment would have helped you in this situation.