Jason doesn't pull back from his attack. His eyes are hidden behind his mask, generally unreadable.

But Eddie might notice two things.

The first is that Jason's not moving quite like would be expected. His moves look more like Dick's than his usual repertoire, but it's not like how Jason would fight when imitating Dick. More like how someone less familiar with Nightwing might think he would fight.

The second is that, before each movement, there's a slight catch, as though he's trying, and failing, to stop himself each time.