Here’s a thread from Reddit with some secrets from flight attendants that will make sure to tickle your nerves once again.
“…if the oxygen masks drop down, you only have about 15 minutes of oxygen from the point of pulling them down. However, that is more than enough time for the pilot to take us to a lower altitude where you can breathe normally.” – jezalenko
“More important – at altitude, you have 15-20 seconds before you pass out. Put yours on first, then do your kids. Passing out for a few seconds won’t harm the kids.” – ksiyoto