Just like for Cal's psychometry, he'll usually register as either nothing at all, or a selection of pretty predictable "stock" fears, like fear of heights, clowns, spiders, etc etc. If he had to put a word to fears he can sense, it would probably be "half-hearted" like they were added as an afterthought.

But very occasionally, the NPCs will ping off with a very real, very visceral fear of NOTHINGNESS, as described in the CrashBang event (prompt 02) where it feels as though the NPCs are terrified of being drained or made void.

These will register very fleetingly to your character, hard to pin down, and will not last very long before being replaced with one of the boring, mundane fears again.