He may have taken Ben's questioning in Locke of why Jack lets him 'talk to him like that' on board.
Incidentally, his change in behaviour when Ben shows up while Locke's talking to Jack in There's No Place Like Home is rather abrupt — he goes from the cool Locke we love to the subordinate Locke some aren't sure of.
His interaction with the Others, whom he's going to lead, but know less than, at least for a time, will be interesting.