I'm wondering if it's a combination of the two, and a physical effect rather than a chemical one. If you run the hydrate plug into a wall, the hydrate at the im

I'm wondering if it's a combination of the two, and a physical effect rather than a chemical one. If you run the hydrate plug into a wall, the hydrate at the impact site will get crushed and release its gas, which has a bigger volume than the original plug. Local pressure goes up so the force of the impact is magnified. That means a smaller impact has potentially an outsized effect. No idea if that works, because otherwise I think you're right. No oxygen, no kaboom. And if there was oxygen present, the leak would be on fire.