From a distance, I couldn’t hear the conversation, but from the gestures I guessed it went something like this:
He, on platform 2: “Is this the platform for Frankston trains?”
She: “No, I think it’s platform 3. Down there, across the tracks.”
So he followed her advice, went down and across the tracks.
Perhaps he should have asked the staff member on duty instead. A Frankston train approached, on platform 2, as I saw him poke his head out on platform 3. He realised the mistake and ran back.
The woman watched too. She slinked away to the very far end of the platform, and put on her sunglasses, perhaps hoping if he missed the train and came back, he wouldn’t be able to identify her.
He ran back onto platform 2 in time, and thanks to the driver pausing to adjust a mirror, just made the train.