NASA actually had a strong focus on safety. They just went about it the wrong way, calculating safety ratings backwards.
Considering the pressure vessel of this sub was only meant to handle 1300m as per another article, the way it survived 50 dives at 4000m is pretty amazing though.
There seems to be a lot of confusion around this, let me try to clear it up.
The 1300m limit of the glass number comes from an interview with the "whistleblower" in 2018. That would mean it refers to the Cyclops 1 vehicle they had then. A couple years later they built the Cyclops 2, which has the 5" thick hull, titanium bells, and first dove in 2021. That's the ill-fated Titan.
If you pay close attention to the videos floating around you'll notice two visibly distinct subs - one with a large transparent dome in front (v1) and one with the titanium bell and tiny porthole (v2).
EDIT: This video (taken from a commenter on this page) includes film of the previous sub, playing next to the guy talking:
https://storage.courtlistener.com/recap/gov.uscourts.wawd.26...