When Kinsey gets a reply from Katie, Kinsey immediately sneaks up after tricking Hillary. Rather than Alex, Zero was more suited to disguise himself as himself. His stature and hair, along with eye color, were similar to him. His face was different, but his body's height, especially his back, was very similar to him.
If people haven't met Zero, they will think the owner of Zero's back was Kinsey's.
Apart from that, Zero has what Kinsey lacks. And just as Kinsey's guessed, Zero had already entered the German government program system. Zero could trick Hillary and find out where his stalker's exact position. That way, the disguise would never be caught.
Once at the place Katie had told him, Kinsey saw a confused Tanya in front of the restaurant.
"Tanya, what are you doing here? Where is Katie?"
"She's in there," answered Tanya, pointing to a restaurant behind them.
