If it's blood, it might be coming from the woman standing a little down the platform from him, keeping just enough distance from the others waiting to be sure not invite casual conversation. Not human blood, though—animal? She tries to cover it with a light perfume, but it's still there.

Blood and something else—it's pretty distinct, if you're familiar with vampires.

Natasha notices him looking around and catches his eye, raising an eyebrow pointedly at the attention.