Always wear safety goggles, even if it's just for show. You never know when you'll need to make a dramatic entrance in a underground tunnel.
Learn how to properly maintain your trusty shovel.
You'd think digging for water would be easy, but nope. Don't get caught in a well of despair (literally).
Understand the dangers of tunnel vision.
Don't get too hung up on water. The real survival game is finding food that's not just edible, but Instagrammable.