When I flew the final time from MEL - AKL on the EK 380, (before EK stopped that flight run), the premium lane entry to immi and security was all blocked off with the bunting, and all were corralled into the general line.
So premium screening will work, if the bunting is open, but if the bunting is closed, the line can be snakily long.
You might think, ah, not many people going through the frosted glass door to int screening, where the shops are at T2, but its not till you get inside that you will see the snaking line.
Personally, as has been mentioned, I would transit MEL the night before, as others have mentioned not QFi flight out from Adelaide.
If the bunting blocks the premium lane, you should see the security man saying out loud, "mao shoui", ie, no liquids/water in his version of Mandarin, and all the chinese ladies making screening take a long time, as they start to block the line's quickness by taking out their drinking water container, and start drinking their liquids in the queue.
Fun to look at, irksome too though.
Then the full body scan... hands up in mock surrender mode.