The pressure differential for a sub at Titanic depth is almost 6,000psi, for a spacecraft in a vacuum it's 14.7psi. It's a very different problem.
It's actually easer to build a balloon than a compressible can.
0.5mm hole in a space craft is a slow leek you can fill with epoxy (it's happened). The same in a sub at the depth of the Titanic, there is no fix and it's not a 0.5mm hole, it's an implosion.