The rabite takes a rather large bite of the branch Zenyatta is holding, and as it is chewing, Zenyatta moves back towards the door. It finishes chewing and then looks for the branch again... which is a few feet away from where it sits. The rabite follows.

The "trick" works for the first two bites, but then the rabite sees the larger one outside. It hops with amazing speed towards it.

Rainbow Dash should have the opportunity to slam the door shut once the rabite is outside.