I did this the other day BNE-LRE-BNE. I couldn’t buy a return and so had two one ways to deliver a box of stuff up there, no checked baggage back.

As I was seated in 2D I was off the plane, through arrivals, went to the loo, security check and in the departure lounge before the last passenger had deplaned.

The Qantas app handled itself brilliantly.