According to the book, the game CAN be manipulated by the operator or the player "in the know".

If the mouse is startled/frightened, it will go in the closest hole. So, the operator could shout something to the players when the mouse was near a couple of numbers that weren't heavily bet. Or a player could bet a group of numbers, then make a noise when the mouse was near that group.

That's why Harold Smith persuaded Raymond that the game had to go.

Memory Lane can provide some great trips!