The problem is not the game controllers, the Home Depot pipes, the trucker toilet, or the camping light, though they do point us vaguely in the direction of the real problem.
The real problem is that this “company” was on a shoe string despite offering an insanely dangerous service, and they did it as cheaply as they could for most things, and even where they were using “high Tech” materials they picked things that would further the ability to run a cheap operation at the expense of safety.
They picked carbon fiber and tungsten because they’re light and strong, and the company is a sketchy operation that can’t afford its own ship and needs to launch from a sled they can move between rentals. If a fucking ballistic missile sub can go neutrally buoyant while made of steel, so could a 5-person day-tripper. Those brittle materials are light and strong and great… until they aren’t, and then they fail catastrophically. The portal, at least at one point, was only rated by the manufacturer for half the depth they intended to go to. They didn’t invest in any way to egress without external assistance. They didn’t do any destructive testing or get type certified because they couldn’t afford another hull. They didn’t buy a god-damned transponder, despite having lost track of the sub at least once before.
Shoot, the Logitech controller and RV light were probably the most reliable things about this death trap.