[Maybe it's both a comfort and another aspect of this shitty situation that he can understand at least enough on the shaken feeling and the way it lingers. He lifts a hand and touches his face, light, just something to ease him, or ground him if he can.]
I know. It's not easy to shake it off. [Clearly that's the point, and the thought just makes him frown more, to think of what the purpose behind this is, of dragging up the past this way, of making implications that are too unfair to Shiro for Keith to stand it.] I'm sorry, Shiro.