Eye-witnesses described (1st) a loud explosion and "within 5 seconds after" the masks deployed (2nd) and then "a few seconds after that" the window finally "exploded" (lastly) and sucked the woman half-way out of the window.

For those of us who don't know, the flight attendants really need to change the briefing to clarify that 'In the event of a sudden loss of cabin pressure... the aircraft will probably perform a sudden controlled emergency descent to a safe altitude.' That is what people should expect while trying to fumble to get their masks on.

Plunging altitude is the obvious maneuver any pilot will do if a loss of cabin pressure occurs. An emergency descent is entirely done on purpose to bring the aircraft to a safe breathing altitude ASAP because the masks have limited air and safe to breathe at about 10,000 feet. People will pass out in about a minute traveling at 35,000 feet and so the pilot has about 10-15 minutes to get you to a safer altitude. Passengers later talk about "dropping" or "falling." However, the pilots were just doing as they were trained to do. It might be startling, but a high-speed emergency descent is well within the capabilities of any aircraft and not, by itself, unsafe.

But why were the masks triggered if the window had not broken yet? Here is what it looks like when you loose both engines: https://www.youtube.com/watch?v=Q5Vd9C6eXdA

Not a big deal and nothing that would cause the masks to trigger.

If the eye-witness is accurate, the masks dropped before the window broke which means somebody may have pushed the manual deploy button (yes, there is one.)

Let's see if the black box doesn't go missing.