Why is it that once mould is growing, and it releases spores, it can grow in or on materials that are not damp?

Question

My home had some flooding recently (from a burst hose connected to a tap, but I'm not sure that's relevant), and in the process of rectifying the situation, a few things were told to me. I'd like some clarification around these statements, and maybe have some misunderstanding on my part cleared up.

1. If the carpet's underlay, and the subfloor are not dried correctly, in a timely manner, there is a risk of mould growing.
2. If mould grows in the carpet, spores will be released, and the mould will start growing everywhere, even in places that are not damp. Even if the underlay is dried too late, mould will still grow.

I feel like this leads to a contradiction. I've got a couple of ideas in my head.

1. The mould grows in the carpet when it is damp, because there are already mould spores in the carpet, and the moisture "activates" them. But this would imply that the spores still would not grow in other places that are not damp, which contradicts what I was told. I'd also be curious as to how the spores got there in the first place.
2. Mould can grow spontaneously in damp places, without mould spores. This sounds quite ludicrous to me, unless perhaps dampness somehow attracts spores, or small animals and insects that carry spores and deposit them. Then once the mould grows in the damp place, spores are released, and because of their proximity, they then grow on other surfaces, despite the lack of moisture. But it requires the dampness to bring the spores in the first place.

Answer 1

Its not that there is no moisture, there is just less and it changes day to day. once mold has stated to grow it saturates the surrounds with spores which means as soon as conditions allow it they grow, whereas normally you need the coincidence of spores happening to be land in the right conditions.

think of it like a fireworks factory, why are they dangerous. Why are fireworks factories, absolutely insane about fire safety. Being in a factory does not make fireworks more flammable, but it does mean any spark has a much better chance of landing on a firework. there is not more sources of fire in a fireworks factory but the factory is "saturated" with something that is highly flammable.

the sheer amount of spores makes it more likely they will find the right conditions at some time during the year. A normal home is someplace mold can grow part of the time but getting those conditions at the same time a spore happens to float in is rare, most spores that make it in will not find the right conditions. Up until you have a lot of moisture, then any spore that floats in finds the right condition, and we go from saturation of moisture to saturation of spores.