Is making a 'bath tub' cover w/ handles made of wood a good idea for tornado safety?

If i go buy a sheet of plywood or OSB, and get it cut to fit the size of my tub, and attach handles w/ screws very securely on the side of the wood that we would facing us in the bathtub, so i could be pulling down on the wood topper if the tub went flying or debris falling on the tub.........is this a good idea...it would just be a piece of wood otherwse and very easy to slide behind the door or somewhere accesible so i could store it away easily