Hmm... I came to the opposite conclusion. The barrier 'took out' Kitty, so I figured losing a form is lethal. But it could just have knocked them unconscious? We're still very much not clear on what happened. (I hope our reporters start asking questions about that. The people want to know!)
For reference:
"I think that barrier is what took out my poor sweet Kitty, so don't bring a familiar if you want it to keep its form."