I've seen a grown man do that, but with a Sig P220.The injury the OP's wife suffered was from having her thumb directly behind the slide and in the path of the slide's rearward travel during recoil like this...
...or sticking straight up like this , both of which are...
He lost some of the top of his left thumb but didn't give up shooting the Sig.
Of course, he never repeated the mistake.