"Dream? What dream? Did anyone say this was a dream? I was not informed of this, no sir."

He twists and turns for a moment, as if reaffirming the reality (or lack thereof) of his surroundings and decides there's no solid difference between a dream or not a dream, and it wouldn't matter very much anyhow, as he's still being judged by this...human? Probably. Humans have that judgmental tendency, don't they?

"No?" says Wheatley. "Funny, that. Look an awful lot like one. Wouldn't make much sense, it's like you're walking around deliberately misleading people. Not very nice, is it? 'Hey, there, I'm a doctor, don't mind the lack of any kind of doctor...paraphernalia...or any of those...associated...things doctors have.' What is it doctors have or do, exactly?"

He's genuinely curious. Aperture Science had its fair share of doctors, but none of them ever stopped to inform him over what the whole meaning of their doctoring was.