[Now, normally Matt would have been prepared for that -- hearing Lancelot walk closer, hearing his heartbeat and breathing and assume concern, feel the air moving as he moves his arm -- but like this, with everything overwhelming his senses, he can't focus properly and despite knowing what Lancelot is about to do... well, he jumps a little anyway.
And makes a face at himself immediately after.]
... Yeah, sorry. Just- got a sudden headache. [Plausible enough, and close to the truth.]