Calling Player flips cards prematurely.

[Dennisa]

I was dealing last night in a tournament. Player A goes all in for 20K. Player B on the button announces call, moves 20K chips into the pot. I start to look at player C the small blind, and commotion starts. I look at B and he has flipped over his cards thinking action is over, but sb/bb have not acted yet. Player A is calling to kill player B's hand. SB/BB have not acted. Floor rules that Player B's hand plays and his 20K plays. sb/bb then fold.