Ziva stood off to the side for a moment, looking between the portal, Nepeta, and Tony. She had a good point, Tony could just let them walk in, and then bail, heading back to the garage and (attempting to) lock himself inside.

"I do not buy that 'ladies first' business. I will take the rear." If only because Tony might need a little kick push to finally get him into the world. And possibly help with balance when he had four legs instead of two.