Not as fancy as you think. Liquid NG is just that, a liquid. So no Hollywood kabooms.
Still you don’t want to be anywhere near them if they go. Once the pressure drops, it is no longer liquid gas. Things get rather interesting. There are a number of Youtube videos showing what happens.
LNG won't even ignite. It first has to be vaporized then diluted with air down to a 15% concentration for ignition.
Once the pressure drops, it is no longer liquid gas.
No, LNG is not really pressurized. "Normal" temperatures are still too hot to compress it into a liquid. The critical temperature of methane is -117°F; above that no amount of pressure will liquefy it.
Since compressing a gas also adds heat, it makes using pressure doubly difficult to liquefy methane. That is why it is done near atmospheric pressures by reducing temperature to -260 °F