Hi everyone!

So I decided to go on a "joyride" of sorts onboard Singapore Airlines to experience the thrill of flying once more, having not flown at all in the past 5 years. I will be flying from Singapore to Brisbane on SQ255, and leaving on SQ236 4.5 hours after arriving in Brisbane, to return to Singapore.

My question would be whether I can do this without a visa (not even a Transit Visa). I started trying to get a Transit Visa too late, and I won't be able to submit the required biometric data before my flights. So the only option now would be to cancel my flights if I really cannot do this turnaround trip without a visa.

Basically all I want to do at the Brisbane Airport is:
1) Get off SQ255;
2) Go get some Australian souvenirs at Australian Way;
3) Visit the Silver Kris Lounge (I am travelling in Business); and
4) Leave on SQ236.

I saw that SQ236 departs from the same gate that SQ255 arrives at. In the absolute worst case scenario, would I be able to just get off SQ255, sit at the gate, and then board SQ236 when the time comes? (I will not be travelling with any checked bags.) The optimal scenario though, would be for me to also visit Australian Way and the SKL.

Looking for the advice of the so-much-more-seasoned travelers here! Thanks in advance!