If product is cooled inside an autoclave without air pressure, there could be a risk to the integrity of the container, especially if glass containers are involved. The absence of air pressure during cooling may cause thermal shock to the containers, which could cause them to rupture or be damaged. In addition, if the containers are not hermetically sealed, they could allow water infiltration during cooling, which could lead to product contamination. Therefore, it is important to control the pressure during cooling to protect both the integrity of the package and the quality of the product.