Ok so he did a clever gimmicky thing but it was style over substance. He was judged "not in a fast food way, not in a masterchef way...." but the others were judged in a Masterchef way.
He didnt show much in the way of technical ability to put together a burger with chips and a drink.
They kept him in because he is good telly, at the expense of others who were far better than him.
Oh and I dont belive for one second that he just happened to pop out and get a set of branded fast food containers, or that it was his idea in the first place.