Bahorel doesn't mean to engage in conversation-- not exactly-- but he at least owes Fauchelevent a thanks in person, if the man's still here. So he raises a hand and calls out in greeting, and starts to walk in Fauchelevent's direction.

But as he draws nearer and sees the other man better, he starts reconsidering what might need to be said.

He'd assumed Hugo was inventing much of the story after the barricades. The spy is still alive, after all. And surely, the old eccentric isn't really--? Well, he can settle the question for himself in conversation soon.