He and Jermaine were bottom of the public vote for favourite housemate (the vote opened before Roxanne turned out to be a pyscho) and the housemates had to choose between them. They voted 4 for each so they had to take another vote and BB just rushed it and Ben got the chop because his name was read first. Jermaine would have been more satisfying with the whole thing about him lying about being married still fresh in the mind.