Sherlock tucks his edge of the blanket in. Finch's reaction is no surprise; if anything, it is validation, confirmation that Sherlock is correct in the brazen limb onto which he's gone out. He's accustomed to shock. He's even accustomed to... this. No, not accustomed, he supposes, there's something particularly frightened about this man's reaction-- but that's surely not Sherlock's doing. Well. It is, obviously, Sherlock's doing. That's beside the point.

Obviously he has touched a nerve. He is well used to ignoring nerves that he's touched, but is not quite sure what to do with them besides that; the man has clearly had a deep well of self-assurance disturbed, if not ease of living in the first place. It has already occurred to Sherlock that someone caught in a bomb blast might live a life of day-to-day safety concerns. It did not really follow for him that saying something might trigger them.

And now he's faced with a man struggling to pull together his composure. Coldly, in Sherlock's mind, it only confirms more things he already knows: that the stranger has enemies. Interesting.

The awkwardness of the moment has not passed. Sherlock thins his mouth and looks away, and says, "Yes." He adds, after some consideration: "You're not the first survivor of a bomb blast that I've met. Though most of the others have been in the military--you've lived an interesting life, haven't you?"