"No, you see, the black mouse tries to kill the white mouse without losing his helmet."
"You mean the helmet can't fall off?"
"Right. If the helmet falls off, even if the black mouse kills the white mouse, it doesn't matter. He loses."
"Even if he's killed the white mouse?"
"Right. He has to kill him with the helmet on. Or, he loses."
"But he's killed him."
"Yeah, so?"
"Doesn't it just matter that he's killed him?"
"Hey, I didn't make the rules. I just put the mice in the box."