I have also found it odd that on all airlines you are told to place your own oxygen mask on before helping your child.
Any parent would find this advice hard to follow - but it is sound common-sense.
Once starved of oxygen, the brain quickly becomes fuddled and confused and, you will probably be incapable of helping anyone else unless your brain is receiving its quota of the precious O2.
In a rapid decompression, the brain will only function usefully for 15-20 seconds before hypoxia kicks in, the dangerous early symptoms of which include confusion and euphoria. That is why it is plainly essential to have your mask on first - whatever your heart tells you!
http://www.consumertraveler.com/colu...sion-accident/
On British Airways aircraft, the oxygen supply in the lavatories is NOT disabled but you should be aware that you will need to pull a streamer to get hold of your mask if you happen to be in the cubicle when something not very nice happens.
I think you should all be aware, too, that there will likely be mist in the cabin briefly as the decompression occurs and that it's nothing to worry about. The "guys in front" will put the aircraft into rapid descent to get down the aircraft down to "breathable air altitude" - what Douglas DC3's and DeHavilland Rapides used to fly at before we went for pressurised airframes.