It ran out the front of the hill, 10 yards from the house. This is key. Your house is not "a mere 20 feet below the ground" as thread parent suggested, it's in

It ran out the front of the hill, 10 yards from the house. This is key. Your house is not "a mere 20 feet below the ground" as thread parent suggested, it's in the side of a hill. This works fine if done correctly, and lots of builders have the experience to do that. It would be difficult to find anyone experienced at the construction of living spaces below 20 feet of soil. Those who do so as amateurs, like that criminal Beckwitt, generally have poor results.