I'm making allowances for those people historically who have rolled amazing strings of critical successes on their HT rolls.
The case history that sticks out to me is
Alexis St. Martin who got shot in the stomach by a musket at close range in 1822 and lived - but "healed" with an open hole into his stomach (a gastric fistula). The doctors didn't have much to do with his living and healing, as expected in 1822.
That was all very interesting to his doctor, who got to study human digestion in a living human by sticking things in through the hole in his side, but not so great for Alexis.
He lived for another 20-odd years before dying after slipping on icy steps.