Another user (Stella) on the forum is in the plumbing business. She and her husband swapped out the shower fixture for a unit with scald guard. It's an option if you're handy.
Also, for those with the newer style shower spay heads with the shut-off valve near the spray head, if one could get a pre-flush warning
, one could hit the water off for the duration of the flush (few seconds) and maybe avert the burn
Jim