Crew close the hatch from the outside with 17 bolts. There’s no other way out

Lost two miles below the surface in the pitch black as your oxygen slowly runs out. Or instant death as the capsule you are crammed inside implodes. Both fates terrify, yet the unthinkable became all-too-real last week as we learned of the fate of the Titanic submersible. Going into an extreme environment for the purpose of pleasure doesn’t give much chance for survival if something goes wrong. But some say it’s part of the allure. Five...