Hell, for all we know crossing the streams might be just fine, but from the look of the effect that the particle cannon is having on the enemies in Wolfenstein, I very much doubt anyone has had the time to consider the implications. They're far too busy screaming and then disintegrating into nothingness. On the plus side, it does look like hats are immune, so all you have to do in order to survive is completely cover your body in hats.
Then take a picture and email it to Owen@Kotaku.com. There's no contest...it just seems like the sort of thing he'd get a kick out of.