Surprising fan theory on how Monk Gyatso best his firebending attackers in Avatar

Here’s a nice and surprising theory about how Monk Gyatso defeated his would be firebending attackers from Avatar: The Last Airbender

This theory was posited by Facebook user Ryan Starkey although this could have been brought up by someone else and then reposted on Facebook.

Here it goes.

How did Monk Gyatso wipe-out about a dozen firebenders, supercharged with Sozin’s comet, before he died?
Here’s my theory: Gyatso knew a secret “last resort” airbending move that Aang was never told about.
As they surrounded him, he sat quietly on the floor. Then, once they were close, he simply pushed all the air out of the room. He held the air out of the room long enough to suffocate all of them, and himself.
Evidence for this:
•His clothing is unburnt, and there is no evidence fire bending was used near him. Why would they have fought/killed him without fire?
•Their bodies are lying piled up around him. If he killed them with airbending, they would have been thrown across the room.
•Aang, as a child, wouldn’t have been taught this dark technique, so it makes sense that it’s not referenced in the show
•We know this type of bending is possible (on a small scale at least) because Zaheer uses it to kill the Earth Queen.
Think about how those firebenders must have felt. Standing over a frail old monk, feeling indestructible from the the power of the comet. Then suddenly, Gyatso pushes his hands to the side, and there’s a rush of noise, then utter silence. They realise they can’t breathe. They try to use firebending to kill him before they suffocate, but without air, there can be no fire!
In one move Gyatso has gone out on his own terms, killed them all, and shown how the elements rely on each other, and the importance of balance.
What do you think?