Vertiginous is inaccurate in his assertions. O2 escaping at high pressure even from a slow leak, can create high temps (adiabatic ) The presence of a small amount of oil/grease can cause ignition. (Check BOC warnings for pressurised O2 cylinders. The YouTube slides show the massive heating and damage caused but no flame explosion.
Explosion - rapid expansion of gases at high pressure. Gases do not have to ignite (ball of flame), but if they do, the explosion is worse & things burn. Knock the HP valve off an O2 cylinder laid flat it will not explode (prob) but rocket across the floor. A restrained canister might 'explode'
What if the Quantas oxygen cyl valve had been hit by shifting cargo?