There are small subs classified to “full ocean depth” (36k feet) with the pressure chambers tested to 150% in labs without a single loss for decades. They are incredibly expensive and only have two chairs in a very cramped cockpit full of *manual* switches/valves for redundant systems (not just a touchscreen and game controller).
The classified subs that go this deep are not suitable for tourists at all and this shmuck was trying to go around every safety consideration to make it so...
He wanted fame and fortune.
He got fame.....................