The movements and the lack of scar would be a dead giveaway if Near were looking at him. But Near rarely bothers to look directly at anyone, so while he notes Mello's presence, he initially does not realize that anything is amiss. So far as he is aware, everything is fine at the moment.

Thus he passes right by him without acknowledgement, not even bothering to stifle a yawn. Yes, he's just gotten up and his mind is still a bit foggy. What are normal sleep schedules? Near knows many things, but that is not one of them.