Fill In The Soil Around It
The last thing you want is for you bunker to be sitting out in the middle of your yard in a dirt pit, so Wayne made sure to use some high-end soil to fill the space surrounding the entrance. That means he can go back once everything is done and plant some plants to help it blend in and fit with the rest of his lawn.
You can see that the finished product won’t even make it look like there was a giant hole there in the first place. And I doubt anyone will expect to find a bunker laying underneath.