... this is what happened!!!
It looks like more than just the file unzipped. Maybe they thought I was trying to sePURRate them, or maybe it was the sound of the zipPURR that irritated them to this extent. I guess I'll never know because they're still too traumatized and neither of them will speak to me. It's the last time I try something like that, I guess.
So I zipped that sucker right back up and now ...
... they're all zipped in and feline secure!