But the others wouldn't let Professor Quirrell keep Harry to himself. It took almost ten minutes to get away from them all. At last, Hagrid managed to make himself heard over the babble.
"Must get on -- lots ter buy. Come on, Harry."
Doris Crockford shook Harry's hand one last time, and Hagrid led them through the bar and out into a small, walled courtyard, where there was nothing but a trash can and a few weeds.
I think 'them' in this context only includes Hagrid and Harry because no others have been mentioned in later context, but I might be wrong. If this is the case, why didn't it put: "led him"(Harry) instead. Or is it idiomatic to include the leader himself in such contexts?