Except, the facts behind Sam's firing will inevitably come out, and it won't be possible to brush it under the carpet. I think they hoped the facts wouldn't come out, and they could just give a hand-wavey explanation, but that's clearly not going to happen. It seems they have well and truly shot themselves in the feet, and they will likely have to be replaced now.
If I'm correct then the board is fine with getting replaced, they just don't want Sam to have total control. Many of the candidates for independent director are friendly with Sam and will happily give him the keys to the kingdom. It's probably extremely difficult to find qualified independent board members who don't have ties to Sam.