TheQuakeSoldier The crackling is from poor audio reception caused by the rise in sound from people gasping. This wasn't that shocking or particularly painful looking, either.
MurgatroidMendelbaum That guy wasn't full of air. The crackling was probably the sound of his ribs detaching from his sternum. And even low-impact crushing chest injuries can be fatal, resulting in several conditions at the same time, such as a pneumothorax, flail-chest, cardiac contusions, and damage to the major vessels.