Interest or eagerness.

At any rate she caught an expression on his face which frightened her.

But not enough to make her run.

And indeed it would have had to be something incredibly awful to scare into a run a girl who had come to the end of her courage to live.
As if encouraged by this glance over the shoulder Captain Anthony came up boldly, and now that he was by her side, she felt his nearness intimately, like a touch.

She tried to disregard this sensation.