The hole Tabitha digging is a weak point for the “monsters”
I think the house collapsing has a big part to do with a flaw in the system or a way to beat this entity. If you think about it Tabitha was digging and the house randomly falls apart. Tabitha was not hitting any structural beams or anything that would cause the house to collapse.
Jim was on the phone and the MIY said “your wife shouldn’t be digging that hole, Jim”. Jim then sees the floor above the hole Tabitha was digging collapse and try’s to get the ruble out and then the whole house collapse. REMEMBER this wasn’t the whole first floor just the parts above the hole that initially collapsed then JIM try’s to free his wife and then the house collapse.
We have to ask ourselves. Why did MIY say “she shouldn’t be digging that hole”
Now REMEMBER the kids were lying down on the stones where they were sacrificed and looking up. When looking up you see the roots and the symbol covering the sky.
WHAT IF - the hole Tabitha was digging is a way to defeat the “monsters” by letting in light into the tunnels where they sleep and have the sacrifices at. Which is why they made the house collapse.