But we can't know what's going on in the cockpit if we aren't told. If the pilot realised he had a pressurisation problem then he should have descended without clearance, and, if he had time, squawked 77 and told ATC.
Precisely, and at this point the only thing he should have to decide is whether the descent should be clean or dirty. Either way he'd probably be coming downhill at around a mile a minute.