Bear in mind, that was Paul commenting on the man's journey. The man may have been fully lucid. Paul doesn't know if the man's physical body ascended or his spiritual body. We aren't told by the man, but from similar experiences I've had, I suspect the man would know he was "dreaming."
Because the term "lucid dreaming" is a fairly recent term, I wonder about other dreams in the Bible. Back then, for all we know, lucid dreams were the norm. The people we read about in the Bible certainly had a more dynamic experience of spirituality (visions, healings, angels, demons, etc), maybe the lucid state of consciousness was commonplace to them. I don't know. Just free-form speculation now

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