Really? Breathing Poo Gas?

This image was brought to my attention by my good friend Brett.

In case it is not immediately apparent, the man pictured, due to some circumstance which is depriving him of breathable air, has inserted a siphon past the water trap of his toilet in order to tap his plumbing for sweet, sweet oxygen. You know this guy is thinking,

"Genius! I'll just breathe poo gas until this fire/sarin gas cloud blows over!"

But you KNOW just two seconds after this guy inhales a mouth-full of poo gas from below his crapper, he's going to say, "Oh Fuck! It's full of poo gas! TAKE ME NOW, LORD!"

Judging from this brilliant escape plan, I imagine he would next fill the bathtub with water, grab a straw and submerge himself until the fire goes out. Ooh ooh! He could also fashion himself a heat proof igloo out of pried ceramic tiles from his bathroom floor.

How did he end up getting stuck in the bathroom anyway? And why are there so many numbers and arrows? There should be just one that reads

Fig. a "Breathe Poo Gas For Great Justice!"

Or better yet:

Escape from fire by trapping yourself in your bathroom.
Shimmy handy siphon into toilet trap.
Breathe poo gas.
FUCK–

Now, I know that by making fun of this clever, yet futile survival technique, I will be ironically thrown into a situation where I myself will have to breathe poo gas to save my life.

As I suckle what little air I can from those fetid pipes, I'll curse the man who wrote the book that tells you to breathe what the water trap in your toilet was built to keep out. I'll curse him for putting that stupid idea into my desperate mind as the conflagration inches ever closer to breaching my hygenic fortress of solitude.

…and if I survive such an encounter, I will tell nobody.