a properly built sub should ride high enough in the water that they could open the hatch on the surface and not take on water

this is of course not a properly built sub

Them being bolted inside is like the cherry on top to me. Sure it's not necessarily dangerous on its own, but add it to everything else about the sub (lack of emergency beacon, only communication via sms, using a knockoff madcatz controller, the general jankiness of the entire design) and having to rely on someone outside to extract you from the death tube even if you do somehow make it to the surface just seems like tempting fate, especially considering the company has lost contact with the "sub" for hours at a time before.

Hell, they didn't even paint the damn thing a visible colour, like orange or red. Imagine you actually make it to the surface in this thing and you still end up suffocating because they have to rely on seeing the stupid thing to find it

People have been fixating on certain details that I think are kind of silly, like them being bolted in from the outside

This isn't my take, SubBrief on YouTube brought this up on his video, but being bolted in and no way to escape in an oxygen rich environment is how the astronauts in Apollo 1 burned to death.

The point being that this company chose to ignore every engineering lesson that was paid for with lives.

It's the final logical conclusion of "move fast and break things"

They'd also drown if they did it at the surface

Not if they had a really big snorkel lol

I understand how that adds to the fear factor and sense of claustrophobia but what the hell would be the point of them being able to open it?

the fact that if you come up somewhere else you don't suffocate while the rescue teams look for you. Allthough I guess "coming up somewhere unknown" wasn't really ever a scenario here.