Upvote:4
A bunch of possible reasons (as also seen from the comments).
but surely in that case you'd want to go all the way through to departures to get them
The person may have very well planned to do that. If you are on a connection, there is nothing that prevents you from walking out of the airport, provided you have enough time and immigration credentials (if needed). I've certainly done that in Heathrow. The only downside is that you have to go through security to get back in.