It looks like they did some worst case testing that was reassuring, so that it isn't Russian roulette? Any comments on that? I suppose their composite testing and temperature projections could also be wrong, and their trajectory changes might not be mitigating enough for the heat shield chunking, but that's a few different things all simultaneously being wrong for a catastrophic failure to occur.
The NASA engineers wanted to understand what would happen if large chunks of the heat shield were stripped away entirely from the composite base of Orion. So they subjected this base material to high energies for periods of 10 seconds up to 10 minutes, which is longer than the period of heating Artemis II will experience during reentry.
What they found is that, in the event of such a failure, the structure of Orion would remain solid, the crew would be safe within, and the vehicle could still land in a water-tight manner in the Pacific Ocean.