There is at least one documented survival at the insane speed of Mach 3: https://theaviationgeekclub.com/bailing-out-at-mach-3-the-in...
http://www.chuckyeager.org/news/sr-71-disintegrated-pilot-fr...
I love the serendipitous detail of what happened on his next flight, though I'm sure it was not so amusing when it happened.
For those out of the loop on the nerd-flex, "Habu" was an unofficial, insidery nickname for the SR-71. It's the name of a venomous snake from somewhere with an SR-71 base (was it Okinawa? I think it was Okinawa), that the locals applied to the plane, because it (like the snake) was black and dangerous-looking.