>> WestJet couldn't offer any details relating to the incident or what caused the plane to aggressively lose altitude.

I am sure that the plane "aggressively lost altitude" because the pilots performed an emergency descend. After the Payne Stewart accident, pilots are made a lot more aware of dangers of pressurization problems. Therefore, once the pilots realized they had a problem, they must have donned their own oxygen masks, and put the aircraft into emergency descend. I can understand why there was no PA announcement during the descend; they should be dealing with the emergency instead of chatting over the PA system.

It appears that the pilots did everything by the book perfectly. Good job to them!

Now if you ever see the oxygen mask deployed in front of you, there is no need to panic. Pull it down firmly to activate the flow of oxygen. Always put your own mask on first before assisting others. Keep in mind that if the masks deploy, pilots probably will put the aircraft into an emergency descend. The spoilers and/or landing gears will cause some rumble, and the air noise may be a bit higher. The pitch angle can also be very extreme. This is all normal, and there is nothing to fear.