'They switched his tanks and he was inhaling pure liquid nitrogen... he's frozen solid.'

AAAAARGH. Regulators!! Pressure!! The part where an oxygen tank would EXPLODE if you filled it full of liquid nitrogen! Heat transfer rates! Humans flinching away from cold weird gases coming out of oxygen masks!

The thing where, when you turn on a LN2 tank, it takes a few minutes for the hose cool off until, you know, LIQUID comes out....