An employee was selecting items and placing them onto a pallet in the freezer section of the warehouse. He stepped backward to move out of the way of another pallet jack operator and his foot got caught in a pallet causing him to stumble. He then grabbed the pallet jack handle to catch himself, twisted the handle which unlocked it, and the jack rolled and caught his foot between the electric pallet jack and the other pallet. The employee sustained a fractured left leg or foot.