Further, I've seen videos of people piercing phone batteries, and it outgasses, but there was no fire. Not saying it's impossible, but at least with phones, it's less likely.
Honestly, if you see a li-ion battery on fire, probably the best thing to do is to run. Throw it somewhere not-very-flammable if convenient, but get the heck out of there. And hold your breath.
And it never actually caught fire. I did however throw it in a chamber we had fashioned for tests that might explode a battery (which this one was not supposed to be). One of my co-workers got the worst of it, and I think he ended up calling out sick the next day. I felt really bad about that.
*edit: Just wanted to add that your advice is still sound. I strongly advise against inhaling that stuff. Better yet, don't cook them, and don't deviate from your procedure just because someone came and asked you for help at precisely that moment.
Note also that lithium-ion batteries over 100 watt-hours are banned too.
A bottle of fluid, by itself, is not likely to be very dangerous. Several bottles + time + privacy--maybe.
As opposed to the one from bottled water?
And you can always dilute it in your air-hostess delivered water if you're so inclined and you just need to have your poison/whatever in liquid form...
Of course, it's a idiotic way to accomplish their goal anyway, but their goal is idiotic anyway, so it's all security theater anyway.
Please, what a frigging joke. Be cooped up in a small bumpy space for hours trying to create a very touchy explosive.
... hydrogen peroxide, acetone, and sulfuric acid ... put a beaker containing the peroxide / acetone mixture into the ice water bath (Champagne bucket), and start adding the acid, drop by drop, while stirring constantly. Watch the reaction temperature carefully. The mixture will heat, and if it gets too hot, you'll end up with a weak explosive. In fact, if it gets really hot, you'll get a premature explosion possibly sufficient to kill you, but probably no one else.
After a few hours - assuming, by some miracle, that the fumes haven't overcome you or alerted passengers or the flight crew to your activities - you'll have a quantity of TATP with which to carry out your mission. Now all you need to do is dry it for an hour or two.
nitro: https://youtu.be/BLB_F2P9pSI?t=3s
phone battery: https://youtu.be/GEo0RhEhFYc?t=19s
Not sure health and safety would have approved of the nitro one.
It's trivially easy to make a lithium fire at 45,000 feet. Stamp on/bend an IMR 18450, and you have a torch which will burn through a window. Hell, you could probably just fold your phone in half - most batteries run the full height of devices these days.