It's not just a sense: the room is quite literally beginning to tilt, but nobody other than Strange and, now, Benedict, seems to notice. The latter takes on a nervous, faraway look when asked to repeat himself-- he clears his throat, opens his mouth, and grimaces as the world shudders beneath his feet.

In another setting, he might shout, panic, do something to protect himself or those around; here, he simply meets Stephen's eyes again, looking quite lost.