He's adept at controlling his reactions when the situation calls for it, but they're in the middle of nowhere, alone. Why would he?

So he lights up in recognition. "Master-" Then, he hesitates, because the face and voice is right, but he could have sworn there was a lot more white in Master Kenobi's hair, last time.

Well, it had been dark, then, and he'd just nearly died of heat exhausion. Maybe he's misrembering.

Moving on. "I know, I know, I shouldn't be here. But I didn't decide to come," Ezra defends, fumblingly try to explain. "It was the Force. Or...the Temple? I just went through the door."