To be honest, my panic dismount wasnt really THAT bad. It was more a case of, i went to pedal, and my legs told me to find someone else to carry me. Truthfully, once you start using clipless pedals, and you get used to the disengagement action, you can pretty much do it without much thought. It becomes another natural muscle memory reflex. Ive had a couple of panic stops from cars and other cyclists darting out, and ive disengaged completely subconsciously without even thinking about it.
I wouldnt stress to much about it, and just continue to work on engaging and disengaging the cleat so that your leg knows what to do. Likewise, dont be like a friend of mine, and only learn how to unclip with one foot. Practice with both, so you always have some options.