MonkSeal once bubbled...
I asked him later what was wrong and he told me he forgot everything because he was focused to my octo's yellow cap.
That is exactly what I was saying. THE
YELLOW OCT is what 99% of divers are trained
INITIALLY to look for. When he saw it around your i am sure he was focused on getting it from your neck. He didn't go for the reg in your mouth because it was already out of you r mouth. In the confusion with all the bubbles and panic I am sure all he could focus on was the octo's yellow cap. When things didn't happen as his training taught him, panic and tunnel vision increase. You should definetly change the color of your Neck back up.
Which is why I said that the DIR (or those who set up their rig utilizing the Hogarthian method) divers need to inform the non-DIR and the divers who use a standard gear config what the deal is with their gear. What is different, what to do in case of OOA emergency, things like that..
However, initial training is also the foundation for instinctive reaction. It is somewhat dangerous to mix training disciplines and expect people to
react a certain way without proper Buddy training and proper predive briefs and planning. These are an absolute must for cross discipline and agency training. I have probably dived with every different type of diving discipline and agency there is (or not) in the past 14 yearsof diving, 7 as a Military Diver, 4 as a Military Dive Instructor. Not everyone knows to go for the primary reg and not the bright yellow one sitting right in front of my eyes, around your neck, not being used.
It does sound as if you did everything you could except for a more thorough pre-dive. I think he was just an Idiot that will be dead next week if not this one. I am a firm believer in proper training or at least (in this case) a good orientation brief. I would buddy with you. Your average buddy given from a boat or whatever wouldnt know 90% of the things you spoke of or did.
Good job and good luck.