Proof that people don't explode when exposed to a vacuum. That seems to be one of the hardest to kill myths of space exploration. Though anyone who's seen 2001 knows it's a myth... Sci Fi movies have notoriously bad science, but Clarke and Kubric tried very hard to get it right.
On a serious note, that had to be a scary experience, and he's lucky he didn't sustain more serious injuries. That could have led to burst eardrums, and boiling could cause damage to delicate tissue, like eyes.