Harry stood quite still, all his senses vibrating, taking in the abrupt return to normality. After a moment, he became aware that his T-shirt was sticking to him; he was drenched in sweat.
I don't quite understand the use of "taking in" in this phrasing "taking in the abrupt return to normality". Should we understand it as [taking] [in the abrupt return to normality] or [taking in] [the abrupt return to normality]? What sense of 'take' is being used here?
I would gloss the phrase as "to experience something via one or more of the senses; to begin to comprehend what one has perceived via one or more of the senses".
Her eyes took in the room.
It took him a few minutes to take in all that she had said.
The cameras flashing, the reporters yelling questions at her, the confetti falling down around her—she was feeling rather overwhelmed as she took it all in.
In the context you cited taking in is used as a phrasal verb, definition #5: To attend or experience, from The Free Dictionary.
Consequently, your quote reads:
Harry stood quite still, all his senses vibrating, attending (experiencing) the abrupt return to normality. After a moment, he became aware that his T-shirt was sticking to him; he was drenched in sweat.
