I feel as if he was set up for failure from the beginning. Emery saddled him with a worthless DC and a inept QB. I think Trest knew it was an uphill battle, but was simply willing to give it a shot since it was his only chance at a HC gig. No HC was going to succeed under those conditions, it was really out of his hands from the start. But now the only solution is to blow the whole things up, starting with the guy that created this mess... Emery.
Id say Phillips, but with as little chance there is of Emery being fired, theres even less a chance they let Phillips go.