When cooking with a pressure cooker the pressure inside is increased. What I mentioned would be operating the pressure cooker at reduced internal pressure.
The pressure would be backwards from how the cooker was designed to operate. It wouldn’t explode but could implode. Pressure cookers operate at about 1 atm gauge pressure with safety limits at 20 psi generally. A hard vacuum inside would be a 14.7 psi difference max - but the wrong way from how the cooker was designed, but the seals look like pressure direction doesn’t matter and domed lids and cylindrical pots are pretty suitable for pressures in either direction.
But thinking about it, it would have to be treated something like a truck tire in a tire shop and used in a protective cage that would contain parts in a failure. And big pressure cookers look around $400 so probably not practical from that standpoint.