"Good job! You're a quick learner!" If her enthusiasm is forced, his seems entirely genuine. This is totally a thing to be excited about!

So! Now they're two humans. That changes things a bit - not a whole lot, but a bit. "There's not really anyone else around," he confides in a lower tone. "Just a few people guarding the doors. I thought if I found some clothes and looked normal, I could get one of them to let me out. I only tried the one door." That person hadn't seemed to recognize him personally - they wouldn't give him his own name. If the others don't know who he is either, they needn't know he's a patient.

It might make more sense for him to stay. He's obviously ill. They just don't seem like they're actually interested in helping anyone around here.