Without going into too much specifics, would it be possible to give us an idea of what the mixing scenario would look like?
What would the baddie need to bring into the lav (I'm assuming this cannot be done at one's seat)? It's rather cramped in there, with not much space to put things down easily whilst juggling vessels. The common impression seems to be that it's a matter of unscrewing one's Gatorade bottle filled with peroxide, scooping in some doctored mascara/shampoo/toothpaste, and shaking the result until it explodes?