[Sherlock was either oblivious to what people might say or more likely he just didn't care, but he took John's hand and very carefully examined it, paying close attention to the bit that was 'burned'. He peered closely at it, and could quickly tell and feel the difference between the quality of his normal skin and that which had the armor.]

Fascinating!

[He's giddy with the promise of scientific discovery that completely overcomes his previous apprehension and fear of the situation he'd found himself in. He lets go of John's hand, his eyes alight with that gleam he got when a particularly gruesome or impossible case appeared.]

John, your cells--do they respond to everything and anything that can harm you?

[He also seemed quite oblivious to how ominous that must have sounded.]