You might be right. I must admit the "fear" I thought I detected was subtle at best, and the word "fear" is just my attempt to assign a word to a response I hadn't seen in him before. I think a better way of describing it is he showed he was "unsettled" at a deeper level than I'd seen before, since generally nothing phases him.

Edit: BellsOnSunday: I'm responding in an edit because for some reason HN doesn't allow me to reply directly to your post.

"Deep, deep terror" does not imply "strong, outwardly expressed terror." By "deep" I meant it was well concealed, deep rooted, and rarely encountered whatever it was. If you replace the word "terror" with "unsettled loss of composure", the sentiment remains the same. The latter is perhaps more accurate, the former takes less words and is what first came to my mind when initially describing it.