Hengist

The Titan does not have an externally opening hatch at all. The surface crew actually bolts and torques the front section of the submersible in place.

Once/if the Titan is located (itself a huge challenge), the only way the Titan can be rescued is by either repairing the submersible underwater so that it can float to the surface under its own power or by affixing a 4km tow cable to it and winching it to the surface. Only at the surface can they crack it open without killing everyone onboard.

I see I'm not the only one thinking that.

Falk: "Why are... millions of dollars in resources, hundreds of people, and dozens of ships and airplanes being... used to look for the lost sub Titan?"

Rescuer: "Well, we are trying to find the submersible because it is lost."

Falk: "Does the submersible contain... more oxygen or a way for the people trapped inside to get to the surface?"

Rescuer: "It has about 40 hours of air left, and there isn't a way for the people to get to the surface."

Falk: "And and and it will take many hours to get another submersible here?"

Rescuer: "... yeah..."

Falk: "I have good news. I have found the submersible. It is in the ocean below us. I have bad news. The people inside are dead. I am Michael Falk. I have found the lost Titan."

100% correct. Game controllers are used in many industrial applications because they are designed to be reliable and durable even in the face of 10 year olds throwing them at walls. They are also interfaced with easy, well-understood protocols and can be easily replaced with off-the-shelf spares.

Where the Titan fails as a submersible is the almost macho and cavalier attitude towards basic safety at almost every level. Simple implements like audio transducers, a sonar system, or even a way to signal when surfaced were skipped in the name of the most bargain-basement craft that could be designed.

Even the use of carbon fiber was a serious red flag. We usually think of carbon fiber as a strong material, and in most cases it is. However, it fails insidiously: it slowly accumulates damage and weakens over time. The active monitoring system they built into the hull, if some sources are to be believed, never worked correctly because of faulty software.

Perhaps the surprise isn't that this whole situation happened. Perhaps the real surprise is that it took this long for disaster to strike.