Our professional pilots will know for sure, but wasn't there an airliner back in the day where a cockpit window blew out, primarily due to a fastener failure, but secondarily because the window was (by design) installed from the outside?I saw a video on the construction of the submersible and couldn’t believe the end with the window was glued on. I’m sure it’s strong glue but still. Many times I’ve seen mentioned how they thumbed their nose at certification and I’d imagine part of the certification process would be stress testing and number of dive cycles it would last.
It sounds like the Titan submersible vessel faced the opposite situation, whereby the window should have been designed to be installed from the outside.
It seems that it would be much safer to have a design whereby the pressure differential forced the window to stay in place, rather than trying to pop it out (in the case of an aircraft) or in (in the case of the submersible).