I was taken aback when I read that it was made of carbon fiber..
You could make a spacecraft using carbon fiber and it would be quite robust but the environment at 2.5mi depth is a lot more hostile than the vacuum of space. spaceships are easy, submarines are hard.
The lunar lander’s thin metal skin was so weak you could jab a pencil through it... like a soda can.
The difference between space and undersea are significant.
To maintain human life in space you need about 14-15 psi internal pressure pushing out on the skin your vehicle. The external pressure pushing in on the skin of your vehicle at the Titanic is about 6000 psi.
That’s a totally different design element.