[Whatever part of him that's startled a little gets immediately suppressed in politeness as Art shakes his head, of course unaware the gesture won't be seen. Nor that his reaction, however slight, already probably gave him away.]
Not at all. Excuse me, I'm only... [checking on suspicions here, no big deal. Rather than lying outright, he breathes out an almost-laugh, deflecting.] I don't believe this facility ordinarily gets much use.