All she can manage is a wide-eyed glance his way before trying to fix a neutral this-is-not-a-big-deal smile on her face as she turns to her brother. It seems to her like it should be obvious-- the Scullys tend to stick out like a sore thumb-- but she's not going to waste time explaining.

"Hi, Bill," she says brightly, like it's not a big deal because she's working very hard to project that nothing interesting is happening. Bill, unfortunately, does not keep going about his business-- he stalks down the hall to where they stand, looking back and forth between the two of them, his gaze landing on Fox.

It's his best Ahab impression, which is not really all that good, but it gets the disapproval across.

"Who is this?"