His perceived himself as nothing more than a low-level teacher of Aikido and his actions were consistant with that role. Had he been capable of handling the TKD man's attack, then the correct way of handling the situation would have been much different. The "aiki" principle in action here was simply that he correctly perceived his role in the situation and acted accordingly
that's strange, I didn't read fear into Mr. Messisco's story. I understand he's quite an accomplished aikido instructor. I think his handling of the situation is top rate instruction on the spirit of Aikido.