[T.B. Yoits]

My understanding of cabin pressure valves is that they're designed to fail into pressurization, and not fail allowing decompression.

Normally a climbing aircraft that failed to pressurize would trip the alarms and have the pilot descend. To depressurize at altitude points to a hatch or glass failing somewhere.

[gibsonguy]

In our case they had to abort a landing for some reason which caused a pressure problem. They make a product called earplane which will prevent a torn eardrum. I would recommend it as a precaution.