Left evidently meant 'straight ahead' because that's where Wheatley went, obvious as always because he was trying to explain how awful Tyler was and how hugging was totally unprofessional. "The Chief isn't even his Test Subject and look how they're carrying on? Indecent."

A portal set him in his place and another brought them right into the menagerie.

There was more than just Walter there.

There were all sorts of strange things. A flying octopus, a giant, 'half invisible' cat, fish that glowed in the dark--

"Huh. So this is what's back there!"