This is just a negotiation tactic. I read somewhere last year that Suter's agent (same as Brunner's) always advised his clients to go to free agency and wait it out. I obviously haven't followed this dude's career or anything, but it looks like the same bag of tricks. Push them to free agency, and wait to see how how teams will go in the scramble. I doubt Detroit goes any higher, but Brunner might well find that he's better off where he was after this all plays out.
He may also find out all the monmey has been spent. I think he will sign within 24 hours. I have no idea where but those that hit the market usually leave their last club.